Apparatus for drug delivery in association with medical or surgical procedures

ABSTRACT

Disclosed are devices for facilitating medical and/or procedures that are performed without “general anesthesia,” which is also described in the specification as the state of patient “unconsciousness” resulting from a drug administered by an anesthetist or anesthesiologist. The devices safely and effectively provide and maintain drug infusions that do not push the patient into unconsciousness and/or general anesthesia. Devices according to embodiments of the invention include the use of stored parameters and/or values that correlate to drug delivery during a procedure, and a patient health monitor to measure and send signals regarding a patient health condition to a processor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/324,759, filed Jun. 3, 1999, now U.S. Pat. No. 6,807,965, issued Oct.26, 2004, which application claims priority to U.S. Provisional PatentApplication Ser. No. 60/087,841, filed Jun. 3, 1998.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates generally to an apparatus and method forrelieving patient pain and/or anxiety. More particularly, this inventionrelates to a system and method for providing sedation, analgesia and/oramnesia to a conscious patient undergoing a painful or anxiety-producingmedical or surgical procedure, or suffering from post-procedural orother pain or discomfort. The invention electronically integratesthrough conservative software management the delivery of one or moresedative, analgesic or amnestic drugs with the electronic monitoring ofone or more patient physiological conditions. In one form, the inventionincludes the use of one or more sets of stored data-defining parametersreflecting patient and system states, the parameters being accessedthrough software to conservatively manage and correlate drug delivery tosafe, cost effective, optimized values related to the consciouspatient's vital signs and other physiological conditions.

BACKGROUND OF THE INVENTION

This invention is directed to providing a conscious patient who isundergoing a painful, uncomfortable or otherwise frightening(anxiety-inspiring) medical or surgical procedure, or who is sufferingfrom post-procedural or other pain or discomfort, with safe, effectiveand cost-effective relief from such pain and/or anxiety. Focuses of theinvention include, but are not limited to, enabling the provision ofsedation (inducement of a state of calm), analgesia (insensitivity topain) and/or amnesia to a conscious patient (sometimes referred tocollectively as “conscious sedation”) by a nonanesthetist practitioner,i.e., a physician or other clinician who is not an anesthesiologist(M.D.A.) or certified nurse anesthetist (C.R.N.A.), in a manner that issafe, effective and cost-effective; the provision of same to patients inambulatory settings such as hospital laboratories, ambulatory surgicalcenters, and physician's offices; and the provision of patientpost-operative or other pain relief in remote medical care locations orin home care environments. To those ends, the invention mechanicallyintegrates through physical proximity and incorporation into an overallstructural system and electronically integrates through conservative,decision-making software management, the delivery of one or moresedative, analgesic or amnestic drugs to the patient with the electronicmonitoring of one or more patient physiological conditions.

In traditional operating rooms, anesthesiologists provide patientsrelief from pain, fear and physiological stress by providing generalanesthesia. “Anesthesia” is typically used (and is so used herein)interchangeably with the state of “unconsciousness.” Over a billionpainful and anxiety-inspiring medical and surgical procedures, however,are performed worldwide each year without anesthesia. Thus, outside thepractice of anesthesiology there are currently a large number ofpatients who, while conscious, undergo medical or surgical proceduresthat produce considerable pain, profound anxiety, and/or physiologicalstress. Such medical or surgical procedures are often performed byprocedural physicians (nonanesthetists) in hospital laboratories, inphysicians' offices, and in ambulatory surgical centers. For example,physician specialists perform painful procedures on conscious patientssuch as pacemaker placement, colonoscopies, various radiologicalprocedures, microlaparoscopy, fracture reduction, wound dressing changesin burn units, and central and arterial catheter insertion in pediatricpatients, in hospital laboratory settings. Primary care physiciansperform such procedures as flexible sigmoidoscopies, laceration repairs,bone marrow biopsies and other procedures in physicians' offices. Manysurgical specialists perform painful procedures such as anterior segmentrepairs by ophthalmologists, plastic procedures by cosmetic surgeons,foreign body removal, transurethral procedures, incisions of neck andaxilla nodes, and breast biopsies in their offices or in ambulatorysurgical centers. The needs of patients for safe and effective pain andanxiety relief during and after such procedures are currently unmet.

Conscious sedation techniques currently available for use by proceduralphysicians (nonanesthetists) during medical or surgical procedures suchas those described above include sedatives and opioids given orally,rectally or intra-muscularly; sedatives and analgesics administeredintravenously; and local anesthetics. Often, however, such techniquesare less than satisfactory.

In the case of oral, rectal or intramuscular administration of sedativesand opioids by procedural physicians during the provision of conscioussedation, there are currently no effective means available to assurethat the effects of those drugs can be readily controlled to meetpatient need. This is due in part to the variable interval betweenadministration and the onset and dissipation of drug effect. Unreliablesedation and analgesia can result because of mismatches between thedosage administered and the patient's needs which can vary depending onthe condition of the patient and the type of procedure performed. Suchadministration of sedation can also produce an unconscious patient atrisk for developing airway obstruction, emesis with pulmonary aspirationor cardiovascular instability. To attempt to avoid these complications,procedural physicians often administer sedatives and analgesicssparingly. This may reduce the risk of major complications, but may alsomean that few patients receive adequate relief from pain and/or anxietyduring medical and surgical procedures outside the practice ofanesthesiology.

The use of intravenous administration of sedatives and analgesics toconscious patients by procedural physicians in settings such as hospitallaboratories, physicians' offices and other ambulatory settings is alsoless than satisfactory. With respect to intravenous bolusadministration, plasma concentrations vary considerably when drugs areinjected directly into the blood stream. This can result in initiallyexcessive (potentially toxic) levels followed by sub-therapeuticconcentrations. Although intravenously administered drugs can betitrated to the patient's need, doing so safely and effectively usuallyrequires the full-time attention of a trained care giver, e.g., ananesthesiologist. Costs and scheduling difficulties among other thingstypically preclude this option.

Due to the difficulties described above involving administration ofsedatives and opioids, many procedural physicians rely on localanesthetics for pain relief. However, local anesthetics alone usuallyprovide inadequate analgesia (insensitivity to pain) for most medicaland surgical procedures and the injections themselves are oftenrelatively painful.

In short, current methods commonly available to procedural physiciansfor providing effective pain relief to conscious patients outside thepractice of anesthesiology typically fall short of the objective.Moreover, there are currently no clear standards of practice fornonanesthetists to guide the relief of pain and anxiety for consciouspatients. There is not adequate training for such practitioners in thediagnosis and treatment of complications that may arise or result fromthe provision of sedation and analgesia to conscious patients.Procedures or mechanisms for ongoing quality management of the care ofconscious patients undergoing painful and anxiety-inspiring medical orsurgical procedures and the devices and methods employed in that careare inadequate.

An additional focus of this invention is the electronic monitoring of aconscious patient's physiological condition during drug delivery, andthe electronic management of drug delivery by conservativedecision-making software that integrates and correlates drug deliverywith electronic feedback values representing the patient's physiologicalcondition, thereby ensuring safe, cost-effective, optimized care.Significantly, in many cases involving conscious sedation, the patient'sphysiological condition is inadequately monitored or not electronicallymonitored at all during drug delivery and recovery therefrom. That is,there is often no electronic monitoring of basic patient vital signssuch as blood pressure, blood oxygen saturation (oximetry) nor of carbondioxide levels in a patient's inhaled and exhaled gases (capnometry).For example, patients undergoing painful procedures in dentists' officesmay receive nitrous oxide (N₂O) gas to relieve pain, but that drugdelivery is often not accompanied by electronic monitoring of apatient's physiological condition, and currently there are no devicesavailable to nonanesthetists which safely and effectively integrateelectronic patient monitoring with such drug delivery mechanisms.

In other circumstances involving the provision of conscious sedation andanalgesia by the procedural physician, such as a cardiologist'sperforming a catheterization procedure in a hospital laboratory,electronic patient monitors are sometimes used, but again, there are nodevices currently available to the nonanesthetist which safely andeffectively integrate both mechanically (through close, physicalproximity and incorporation into a structural system), andelectronically (through conservative software management), electronicpatient monitors with mechanisms for drug delivery.

One aspect of the invention of this application is directed to thesimplification of drug delivery machines for relieving patient pain andanxiety by eliminating features of those machines that complicate theprovision of patient pain and anxiety relief, and by including thosefeatures that enable nonanesthetists to provide safe, cost-effective,optimized conscious sedation and analgesia. More specifically, currentanesthesia machines used by anesthesiologists to provide generalanesthesia and a form of conscious sedation administered by theanesthesiologist known as “monitored anesthesia care” (MAC) includevarious complex features such as oxygen (O₂) flush valves which arecapable of providing large amounts of oxygen to the patient at excessivepressures, and carbon dioxide (CO₂) absorbent material which absorbs CO₂from a patient's exhaled gases. In addition, anesthesia machinestypically deliver halogenated anesthetic gases which can triggermalignant hyperthermia. Malignant hyperthermia is a rare, but highlycritical condition requiring the advanced training and skills of ananesthesiologist for rapid diagnosis and therapy. The airway circuit incurrent anesthesia machines is circular in nature and self-contained inthat the patient inhales an oxygen/anesthetic gas mixture, exhales thatmixture which is then passed through CO₂ absorbent material, re-inhalesthe filtered gas mixture (supplemented by additional anesthetic andoxygen), and repeats the process.

These aspects of anesthesia machines, among others, carry attendantrisks for the patient such that anesthesia machines require operation bya professional trained through a multi-year apprenticeship (e.g., ananesthesiologist or C.R.N.A.) in detecting and correcting failure modesin the technology. For example, an oxygen flush valve can cause oxygento enter a patient's stomach thereby causing vomiting; and carbondioxide absorbent material can fail in which case the patient couldreceive too much carbon dioxide if the failure was not promptly detectedand corrected. Moreover, the use of the self-contained, circular airwaycircuit could result in a circumstance whereby if the supply of O₂suddenly ceased, a patient would only be breathing the finite supply ofoxygen with no provision for administration of additional requirementsfor O₂ or atmospheric air. Such features, among others, make anesthesiamachines unusable by nonanesthetists. Therefore, a focal point of thisaspect of the invention is the simplification of a drug deliveryapparatus by selecting and incorporating the appropriate features tofacilitate the rendition of safe and effective conscious sedation bynonanesthetists.

Certain aspects of this invention also focus on ensuring maintenance ofpatient consciousness to prevent airway difficulties, includingmonitoring the level of patient consciousness during the delivery of oneor more sedative, analgesic and/or amnestic drugs to a conscious,non-intubated, spontaneously-ventilating patient to prevent airwaydifficulties. For patients not intubated on a ventilator, monitoring thelevel of patient consciousness is important to provide information aboutthe likelihood of depressed airway reflexes and respiratory drive tobreathe, the ability to maintain a patent airway, and the likelihood ofcardiovascular instability. Despite the importance of monitoring andmaintaining adequate levels of consciousness in certain medicalsettings, there is no currently available device for ensuringmaintenance of patient consciousness by integrating mechanically andelectronically such monitoring of a patient's level of consciousnesswith a drug delivery system. The invention of this application isdirected to this unmet need, as well.

This invention is also directed to providing conscious patients relieffrom pain and/or anxiety in a manner that is cost-effective and timeefficient. Current solutions for relieving patient pain and anxiety bydrug delivery and electronic monitoring of a patient's physiologicalcondition are expensive and require a great deal of time to set-up andtake down. Also, the current requirement or desire for the presence ofan anesthesiologist during some medical or surgical procedures increasescosts, especially if that desire requires in-patient care as opposed tocare in an ambulatory setting. To the extent medical procedures areperformed on conscious patients without adequate sedation and analgesiadue to the current unavailability of appropriate methods and devices forproviding such care (e.g., wound dressing changes in burn wards), suchprocedures may need to be conducted on numerous occasions, but overshort periods of time (due to a patient's inability to tolerate thelevel of pain), as opposed to conducting a fewer number of moredefinitive procedures. The requirement of multiple sessions of care alsotypically involves increased costs. This invention addresses suchcost-effectiveness concerns and provides solutions to problems such asthose described.

The invention is further directed to the provision of relief frompost-operative or other post-procedural pain and discomfort in remotemedical care locations and home care type settings. Current devices maypermit certain patients in, for example, a home care type setting, toprovide themselves with an increased dosage of analgesic through the useof a patient-controlled drug delivery device, e.g., a device thatpermits a patient to press a button or toggle a switch and receive moreanalgesic (often intravenously or transdermally). This practice issometimes called “PCA” or patient-controlled analgesia. Knowncommercially available PCA-type devices do not electronically integrateand conservatively manage delivery of analgesics in accord with theelectronic monitoring of a patient's physiological condition. Thisinvention focuses on this unmet need, as well.

An additional aspect of this invention is directed to the integration ofa billing/information system for use with an apparatus providingsedation, analgesia and/or amnesia to conscious patients in physician'soffices, hospital laboratory or other ambulatory settings or remotemedical care locations. Current techniques for automated billing andinvoice generating provide inadequate and inefficient methods fortracking recurring revenues derived from repeated use of medical devicessuch as the apparatus of this invention.

Other focuses of the invention are apparent from the below detaileddescription of preferred embodiments.

DESCRIPTION OF RELATED ART

Known machines or methods administered by the nonanesthetist forproviding conscious, non-intubated, spontaneously-ventilating patientswith sedation and analgesia are unreliable, not cost-effective or areotherwise unsatisfactory. No commercially available devices reliablyprovide such patients with safe and cost-effective sedation, analgesiaand amnesia to conscious patients by integrating and correlating thedelivery of sedative, analgesic and/or amnestic drugs with electronicmonitoring of a patient's physiological condition. Available drugdelivery systems do not incorporate a safety set of defined dataparameters so as to permit drug delivery to be conservatively managedelectronically in correlation with the patient's physiologicalconditions, including vital signs, to effectuate safe, cost-effectiveand optimized drug delivery to a patient. Available drug deliverysystems do not incorporate alarm alerts that safely and reliably freethe nonanesthetist practitioner from continued concern of drug deliveryeffects and dangers to permit the nonanesthetist to focus on theintended medical examination and procedure. Moreover, there are no knownpatient-controlled analgesia devices that mechanically andelectronically integrate and correlate (through conservative softwaremanagement) patient requests for adjustments to drug dosage andelectronic monitoring of patient physiological conditions.

Known techniques have focused on the delivery of sedation and analgesiato conscious patients with inadequate or no electronic monitoring ofpatient physiological conditions, including vital signs, and noelectronic integration or correlation of such patient monitoring withdrug delivery. Other techniques have focused on the provision ofanesthesia to unconscious patients with the requirement of ananesthesiologist to operate a complicated, failure-intensive anesthesiamachine.

Presently known nitrous oxide delivery systems such as thosemanufactured by Matrx Medical, Inc., Accutron, Inc., and others are usedprimarily in dental offices for providing conscious sedation only. Suchdevices contain sources of nitrous oxide and oxygen, a gas mixing deviceand system monitors, but no mechanical or electrical integration ofpatient physiological condition monitors with drug delivery mechanisms.Similarly, other known drug delivery systems (e.g., intravenous infusionor intramuscular delivery mechanisms) for providing sedatives andanalgesics to conscious patients used, for example, in hospitallaboratories, do not include mechanical or electronic integration ofpatient physiological condition monitors with drug delivery mechanisms.

Anesthesia machines used by anesthesiologists to provide generalanesthesia or MAC, such as, by way of example, the NARKOMED line ofmachines manufactured by North American Drager and EXCEL SE ANESTHESIASYSTEMS manufactured by Ohmeda Inc., mechanically integrate electronicpatient monitors in physical proximity to drug delivery mechanisms.These machines, however, employ features such as O₂ flush valves,malignant hyperthermia triggering agents, CO₂ absorbent material, aswell as circular airway circuits, among others, thereby requiringoperation by an M.D.A. (or C.R.N.A.), to avoid the occurrence oflife-threatening incidents. These devices do not provide for theelectronic integration or management of drug delivery in correlationwith the monitoring of a patient's physiological condition, much lesssuch electronic management through conservative, decision-makingsoftware or logic incorporating established safe data-definingparameters.

U.S. Pat. No. 2,888,922 (Bellville) discloses a servo-controlled drugdelivery device for automatic and continuous maintenance of the level ofunconsciousness in a patient based on voltages representative of thepatient's cortical activity obtained by means of anelectroencephalograph (EEG). The device continuously and automaticallyincreases or decreases in robotic fashion the flow of anesthetic gas (orI.V. infusion) in response to selected frequencies of brain potential tomaintain a constant level of unconsciousness.

U.S. Pat. No. 4,681,121 (Kobal) discloses a device for measuring apatient's sensitivity to pain during the provision of anesthesia, byapplying a continuous, painful stimulus to the nasal mucosa andregulating the level of anesthesia in response to EEG signals indicatingthe patient's response to the nasal pain stimulus, with the goal ofmaintaining a sufficient level of unconsciousness.

Among other things, none of the above-described known devices managesdrug delivery to conscious patients employing conservativedecision-making software or logic which correlates the drug delivery toelectronic patient feedback signals and an established set of safetydata parameters.

SUMMARY OF THE INVENTION

The invention provides apparatuses and methods to safely and effectivelydeliver a sedative, analgesic, amnestic or other pharmaceutical agent(drug) to a conscious, non-intubated, spontaneously-ventilating patient.The invention is directed to apparatuses and methods for alleviating apatient's pain and anxiety before and/or during a medical or surgicalprocedure and for alleviating a patient's post-operative or otherpost-procedural pain or discomfort while simultaneously enabling aphysician to safely control or manage such pain and/or anxiety. Thecosts and time loss often associated with traditional operating roomsettings or other requirements or desires for the presence ofanesthetists may thus be avoided.

A care system in accordance with the invention includes at least onepatient health monitor which monitors a patient's physiologicalcondition integrated with a drug delivery controller supplying ananalgesic or other drug to the patient. A programmable,microprocessor-based electronic controller compares the electronicfeedback signals generated from the patient health monitor andrepresenting the patient's actual physiological condition with a storedsafety data set reflecting safe and undesirable parameters of at leastone patient physiological condition and manages the application ordelivery of the drug to the patient in accord with that comparison. In apreferred embodiment, the management of drug delivery is effected by theelectronic controller via conservative, decision-making softwareaccessing the stored safety data set.

In another aspect the invention also includes at least one system statemonitor which monitors at least one operating condition of the caresystem, the system state monitor being integrated with a drug deliverycontroller supplying drugs to the patient. In this aspect, an electroniccontroller receives instruction signals generated from the systemmonitor and conservatively controls (i.e., curtails or ceases) drugdelivery in response thereto. In a preferred embodiment, this isaccomplished through software control of the electronic controllerwhereby the software accesses a stored data set reflecting safe andundesirable parameters of at least one operating condition of the caresystem, effects a comparison of the signal generated by the system statemonitor with the stored data set of parameters and controls drugdelivery in accord with same, curtailing or ceasing drug delivery if themonitored system state is outside of a safe range. The electroniccontroller may also activate attention-commanding devices such as visualor audible alarms in response to the signal generated by the systemstate monitor to alert the physician to any abnormal or unsafe operatingstate of the care system apparatus.

The invention is further directed to an apparatus which includes a drugdelivery controller, which delivers drugs to the patient, electronicallyintegrated with an automated consciousness monitoring system whichensures the consciousness of the patient and generates signal valuesreflecting patient consciousness. An electronic controller is alsoincluded which is interconnected to the drug delivery controller and theautomated consciousness monitor and manages the delivery of the drugs inaccord with the signal values reflecting patient consciousness.

In another aspect, the invention includes one or more patient healthmonitors such as a pulse oximeter or capnometer and an automatedconsciousness monitoring system, wherein the patient health monitors andconsciousness monitoring system are integrated with a drug deliverycontroller supplying an analgesic or other drug to the patient. Amicroprocessor-based electronic controller compares electronic feedbacksignals representing the patient's actual physiological conditionincluding level of consciousness, with a stored safety data set ofparameters reflecting patient physiological conditions (includingconsciousness level), and manages the delivery of the drug in accordwith that comparison while ensuring the patient's consciousness. Inadditional aspects of the invention the automated consciousnessmonitoring system includes a patient stimulus or query device and apatient initiate response device.

The invention also provides apparatuses and methods for alleviatingpost-operative or other post-procedural pain or discomfort in a homecare-type setting or remote medical care location. Here the care systemincludes at least one patient health monitor integrated withpatient-controlled drug delivery. An electronic controller manages thepatient-controlled drug delivery in accord with electronic feedbacksignals from the patient health monitors. In a preferred embodiment theelectronic controller is responsive to software effecting conservativemanagement of drug delivery in accord with a stored safety data set.

DESCRIPTION OF THE DRAWINGS

Other objects and many of the intended advantages of the invention willbe readily appreciated as they become better understood by reference tothe following detailed description of preferred embodiments of theinvention considered in connection with the accompanying drawings,wherein:

FIG. 1 is a perspective view of a preferred embodiment of a care systemapparatus constructed in accordance with this invention, depicting theprovision of sedation, analgesia and/or amnesia to a conscious patientby a nonanesthetist.

FIG. 2 is a perspective view of a preferred embodiment of a care systemapparatus constructed in accordance with this invention depicting userinterface and patient interface devices.

FIGS. 3A and 3B are side-elevational views of a preferred embodiment ofan apparatus constructed in accordance with this invention.

FIG. 4A is a block diagram overview of the invention.

FIG. 4B is an overview data-flow diagram depicting the drug deliverymanagement aspect of the invention.

FIG. 5 depicts a preferred embodiment of the invention.

FIG. 6 depicts a preferred embodiment of a drug delivery system inaccordance with the invention.

FIGS. 7A–7C depict the details of a preferred embodiment of the drugsource system in accordance with the invention.

FIG. 8 depicts a preferred embodiment of an electronic mixer system inaccordance with the invention.

FIG. 9A depicts one embodiment of a manifold system in accordance withthe invention.

FIG. 9B depicts a second embodiment of a manifold system in accordancewith the invention.

FIG. 10A depicts a preferred embodiment of a manual bypass system inaccordance with the invention.

FIG. 10B depicts a preferred embodiment of a scavenger system inaccordance with the invention.

FIG. 11 depicts a preferred embodiment of a patient interface system inaccordance with the invention.

FIGS. 12A and 12B are a front perspective view and a side-elevationalview, respectively, of a preferred embodiment of hand cradle deviceconstructed in accordance with the invention.

FIGS. 13A and 13B are rear perspective views of a preferred embodimentof hand cradle device constructed in accordance with the invention.

FIGS. 14A and 14B are, respectively, a front perspective view of analternative embodiment of a hand cradle device constructed in accordancewith this invention and a top plan view of a patient drug dosage requestdevice in accordance with the invention.

FIG. 15 shows a perspective view of a preferred embodiment of theinvention, including a hand cradle device and an ear piece combinationoximeter/auditory query device.

FIG. 16 is a side-elevational view of an ear piece placed within apatient's ear containing a pulse oximetry sensor and an auditory queryin accordance with the present invention.

FIG. 17 depicts an alternative preferred embodiment of a care systemapparatus constructed in accordance with the invention.

FIG. 18 depicts a user interface system in accordance with a preferredembodiment of the invention.

FIGS. 19A and 19B depict the various peripheral devices included in apreferred embodiment of the invention.

FIG. 20 depicts a preferred embodiment of a patient information/billingsystem in accordance with the invention.

FIG. 21A depicts examples of drug delivery management protocols for3-stage alarm states reflecting monitored patient parameters inaccordance with the invention.

FIG. 21B depicts examples of drug delivery management protocols for2-stage alarm states reflecting monitored system state parameters inaccordance with the invention.

FIG. 22A depicts a first embodiment of a user interface screen displayin accordance with the invention.

FIG. 22B depicts a second embodiment of a user interface screen displayin accordance with the invention.

FIG. 23A is a data-flow diagram depicting an example of the stepsperformed by the drug delivery management software or logic responsiveto patient health monitors in accordance with the invention.

FIG. 23B is a data-flow diagram depicting an example of the stepsperformed by the drug delivery management software or logic responsiveto system state monitors in accordance with the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiments illustrated below are not intended to be exhaustive orto limit the invention to the precise forms disclosed. The embodimentsare chosen and described in order to explain the principles of theinvention and its applications and uses, and thereby enable othersskilled in the art to make and utilize the invention.

FIG. 1 shows a care system 10 constructed in accordance with thisinvention, providing sedative, analgesic and/or amnestic drugs to aconscious, non-intubated, spontaneously-ventilating patient undergoing amedical or surgical procedure by a procedural physician. The system 10has a generally columnar housing 15 with various storage compartments 16therein for storage of user and patient interface devices, and a base 17supported on castor wheels 18. A drug delivery system 40 delivers amixture of one or more gaseous sedative, analgesic or amnestic drugs incombination with oxygen (O₂) gas to a patient, and includes a one-wayairway circuit 20 connected at one end to a face mask 30 and at theother end to a manifold valving system contained within housing 15.FIGS. 3A and 3B show from a side-elevation perspective, airway circuit20, face mask 30, and exhaust hose 32 through which scavenged patientexhaled gases are exhausted to a safe location.

Referring to FIG. 2, lead 50 connects one or more patient interfacedevices (e.g., 55) to a microprocessor-based electronic controller orcomputer (sometimes also referred to herein as main logic board, MLB)located within housing 15. The electronic controller or main logic boardmay be comprised of combinations of available programmable-typemicroprocessors and other “chips,” memory devices and logic devices onvarious board(s) such as those manufactured by Texas Instruments (e.g.,XK21E) and National Semiconductor (e.g., HKL 72, among others. Patientinterface devices 55 can include one or more patient health monitorsthat monitor a patient's physiological condition, such as known pulseoximeter, capnometer (not shown), non-invasive blood pressure monitors;EKG, EEG, acoustical monitors (not shown), and others; an automatedconsciousness monitoring system, including query initiate and responsedevices in accordance with the invention (described below); and patientdrug dosage request devices (also described below). The main logic boardelectronically manages operation of the apparatus 10 by means ofconservative, decision-making software that integrates and correlatespatient feedback signals received from the one or more patient healthmonitors with drug delivery.

Also shown in FIGS. 1 and 2 are various user interface devices,including a display device 35 integrated into the top surface ofapparatus 10 which displays patient and system parameters and operationstatus of the apparatus, a printer 37 which prints, for example, a hardcopy of patient parameters indicating the patient's physiologicalcondition and the status of various system alarms with time stamps, anda remote control device 45 which permits a physician to interact withapparatus 10. The various patient and user interface devices aredescribed in more detail below.

It should be recognized that although certain embodiments of theinvention show the analgesic delivery system 40 in a form for deliveringone or more sedative, analgesic or amnestic drugs in gaseous form, theinvention also specifically includes embodiments where such drugs aredelivered intravenously, in nebulized, vaporized or other inhaled form,and/or transdermally such as by using known ion-transfer principles.Drugs that may be delivered by the care system include, but are notlimited to, nitrous oxide, propofol, remifentanil, dexmedetamidine,epibatadine and sevoflurane. Alternative embodiments are described inmore detail herein.

FIG. 4A is a block diagram overview of a preferred embodiment of theinvention. FIG. 4B is an overview data flow diagram depicting the drugdelivery management steps performed by the software/logic control ofmicroprocessor controller 14 in a preferred embodiment of the invention.In FIG. 4A, one or more patient health monitors 12 a (which may includeone or more known patient physiological condition monitors such as pulseoximeters, capnometers, other ventilatory monitors, non-invasive bloodpressure monitors, EKG, EEG and others, as well as a patientconsciousness monitoring system) are electronically coupled, throughsuitable A-D converters where appropriate, to electronic controller 14,described above. Patient health monitors 12 a generate electronicfeedback signals representing actual patient physiological data whichare converted to electronic signals and then provided to controller 14.Now referring to FIG. 4B, electronic controller 14, e.g., throughappropriate software and/or logic, compares the received electronicpatient feedback signals 13 b with the safety data set 15 b stored in amemory device (such as an EPROM device).

The stored safety data set 14 a (FIG. 4A) contains at least one set ofdata parameters representing safe and undesirable patient physiologicalconditions. Based on the comparison of the actual monitored patientphysiological data 13 b with the safety data set 14 a, controller 14determines whether the monitored patient physiological data is outsideof a safe range (FIG. 4B, 16 b). If the monitored patient data isoutside of a safe range, electronic controller 14 sends instructioncommands (signals) to drug delivery controller 2 a (FIG. 4A) instructingdrug delivery controller 2 a to conservatively manage (e.g., reduce orcease) drug delivery (FIG. 4B, 18 b). Drug delivery controller 2 a maybe a standard solenoid valve-type electronic flow controller known tothose skilled in the art.

As is described below, additional embodiments of the invention alsocontemplate provision of electronic feedback signals representingpatient-controlled drug dosage increase or decrease requests tocontroller 14 and electronic management of drug delivery inconsideration of such patient requests vis-a-vis the patient'sphysiological parameters and/or the state of the care system.

A block diagram of a preferred embodiment of a care system in accordancewith the invention is depicted in FIG. 5. Analgesic delivery system 2 ofFIG. 5 delivers a mixture of gaseous sedative, analgesic and/or amnesticdrugs (such as nitrous oxide, sevoflurane or nebulized narcotics) andoxygen gas to the patient. Manual bypass circuit 4 (shown in furtherdetail in FIG. 6 and FIG. 10A) is coupled to the manifold system portionof analgesic delivery system 2 and bypasses the source of analgesiaenabling the manual control of delivery of atmospheric air to thepatient. An auxiliary inlet 6 is provided to analgesic delivery system 2and enables the provision of in-house supply of gaseous drug or oxygento the delivery system 2. Scavenger system 8 (shown in detail in FIG.10B) is coupled to analgesic delivery system 2 and collects exhaledgases from the patient and exhausts them to a safe location throughexhaust hose 32 (FIG. 3B).

Patient interface system 12 includes one or more patient health monitors(these can be known vital sign monitors, such as non-invasive bloodpressure monitors, or known pulse oximeters, capnometers, EKGs, etc.);means for monitoring the level of a patient's consciousness; and/ormeans for the patient to communicate with system 10 (FIG. 1), such as byrequesting an increase or decrease in the dosage of drugs. One or moreof these patient monitoring and request devices are electronicallycoupled to and, through A-D converters, provide feedback signalsrepresenting the patient's actual physiological condition and drugdosage requests to electronic controller 14. Controller 14 compares thiselectronic feedback received with data stored in a memory device, saiddata representing sets of one or more safe and undesirable patientphysiological condition parameters (e.g., safe and undesirable O₂saturation conditions, end tidal CO₂ levels and/or levels of patientconsciousness). These sets of parameters are collectively referred to asa safety data set. Based on the comparison, controller 14 commandsconservative application of drug delivery in accord with said parametersat safe, cost-effective optimized values.

Still referring to FIG. 5, user interface system 16 (described in moredetail in FIGS. 18 and 22) displays electronic signal values stored inor provided to electronic controller 14, such values reflecting thestatus of one or more of the patient's physiological state, thepatient's level of consciousness, and/or the status of various caresystem parameters. User interface system 16 includes devices that permitthe nonanesthetist to interact with the care system via controller 14(e.g., input patient information, pre-set drug dosages, silence alarms)such as keyboard 230 (FIG. 2) and/or remote control unit 45 (FIG. 1).Patient and care system information is displayed by means of graphicaland numeric display devices, e.g., 35 (FIG. 1), LEDs incorporated intohousing 15 (FIG. 1) and/or on remote control unit 45.

External communication devices 18 (also described in FIGS. 19A and 19B)enable the sending and/or receiving of electronic information signals toand from electronic controller 14 and external computers at remotelocations or on local networks. Peripheral devices 22 such as door andtemperature sensors, among others, communicate electronically withcontroller 14 to ensure the proper, safe and secure operation of caresystem 10.

The above systems overviewed in FIG. 5 are now described in more detail.

FIG. 6 shows in further detail an overview of a preferred drug deliverysystem 2 (FIG. 5) which provides a mixture of one or more sedative,analgesic and/or amnestic drugs in gaseous form; oxygen; and atmosphericair to a patient, the provision of each being independently adjustable(manually and via electronic controller 14) by the physician. The drugdelivery system is comprised of a drug source system 42, an electronicmixer system 44 and a manifold system 46.

Drug source system 42 contains sources of one or more gaseous drugs andoxygen and is coupled through pneumatic lines to electronic mixer system44. Drug source system 42 is also electronically coupled to electroniccontroller 14, and as is described below, contains sensors monitoringone or more operating states of drug source system 42 (e.g., whether thedrug is flowing). Such monitored system information is converted toappropriate electronic signals and fed back to electronic controller 14via the electronic coupling.

Electronic mixer 44 receives the one or more gaseous drugs, O₂ andatmospheric air through the pneumatic lines and electronically mixessame. Electronic mixer 44 is also electronically coupled to electroniccontroller 14 and also contains sensors that provide electronic feedbacksignals reflecting system operation parameters of mixer 44 to electroniccontroller 14. Mixer 44 includes electronic flow controllers withsolenoid valves which receive flow control instruction signals fromcontroller 14.

Manifold system 46 is coupled through pneumatic lines to and receivesthe one or more gaseous drugs, O₂ and air mixture from electronic mixer44 and delivers the mixture to the patient via airway circuit 20(FIG. 1) and face mask 30 (FIG. 1). Manifold system 46 is alsoelectronically coupled to electronic controller 14 and includes sensorsthat provide electronic feedback signals reflecting manifold system 46operation parameters to controller 14. Manifold 46 delivers patientexhaled gases to a scavenging system 48 for exhaust to a safe locationvia exhaust hose 32 (FIG. 3B).

Drug source system 42 is shown in further detail in FIGS. 7A–7C.Referring to FIG. 7A, analgesic source system includes drug sourcesystem 142 which provides a source of one or more sedative, analgesicand/or amnestic drugs; and an oxygen source system 144 which provides asource of oxygen. In aspects of this invention where the drugs are ingaseous form, the sources of drugs and oxygen provide the gases at lowpressure, and can be tanks contained within housing 15 (FIG. 1) such asthose shown at numeral 54 in FIG. 2 or an in-house source. The abilityto use alternative sources increases the useability of the care systemof the invention because the system can function as a source-dependentunit within rooms with access to in-house gas supplies or as aself-contained unit within rooms that do not have in-house gasconnections.

In additional aspects of the invention, drug source system 42 caninclude one or more of the following: known nebulizers 143 which enablethe delivery of aerosolized drugs, such as morphine, meperidine,fentanyl and others; known vaporizers 145 which enable the delivery ofhalogenated agents, such as sevoflurane; known infusion pump-type drugdelivery devices 147 or known transdermal-type drug delivery devices 149(including ion transfer based devices) to enable the delivery of drugssuch as propofol, remifentanil, and other infusible drugs by continuousor bolus administration.

FIG. 7B details the oxygen source system and shows an oxygen tank orother source of oxygen 104 and a pneumatic oxygen line 109 fordelivering oxygen gas to electronic mixer system 44 (FIG. 7A). Filter106 a in oxygen line 109 removes contaminants within the oxygen streamfrom oxygen source 104. Pressure sensor 106 (which may be of a typeknown and currently available) in oxygen line 109 monitors the pressurein oxygen source 104 generating a signal reflecting same and therebyindirectly measuring the amount of oxygen remaining. Pressure sensor 106is electronically coupled to electronic controller 14 and forwardssignals reflecting the measure of pressure in the oxygen source tocontroller 14. In a preferred embodiment, electronic controller 14receives the signal from pressure sensor 106 and through softwareaccesses data parameters stored in a memory device. The parametersreflect one or more setpoints establishing safe and undesirableoperating conditions of O2 operating pressure. Controller 14 comparesthe actual O2 pressure to the stored parameter set point data. If thecomparison reveals that the O2 pressure is outside of an establishedsafe range as established by the stored data, an alarm or otherattention-commanding device activates and if same is not manuallydeactivated, electronic controller 14 instructs the flow of drugdelivery to reduce to a pre-set safe amount (or cease). The operation ofthe software control vis-a-vis system state monitors is described inmore detail in connection with FIGS. 21A and 23A.

The signal obtained from oxygen source pressure sensor 106 can berelated to the user via display devices (e.g., 35, FIG. 2) in terms ofthe time remaining under present use so that the user can ascertain ifthe procedure can be completed. The user is immediately notified if thepressure falls out of the normal operating conditions by an alarm,display device or other suitable attention-commanding device. Pressuregauges 108 visually display to the user the oxygen source pressureobtained by sensor 106. Pressure regulator 110, which may be of a knownsolenoid type currently available or other suitable regulator, enablesthe reduction of pressure in oxygen source 104 to a reasonable operatingpressure to provide flow of O₂ to the patient. Check valve 112 (checkvalves may be of a standard one-way type), in oxygen line 109 downstreamof regulator 110 prohibits backward flow of the patient's exhalationsand ensures that such back-flow does not damage or contaminate regulator110 and oxygen source 104. In systems where an in-house oxygen source105 is used, remote check valve 114 ensures that back-flow from thepatient's exhalations does not damage or contaminate in-house oxygensource 105. Pressure relief valve 116 exhausts oxygen to the atmosphereif the pressure in oxygen line 109 exceeds safe operating valuespre-programmed into electronic controller 14.

FIG. 7C details the drug source system and in a preferred embodimentincludes a tank or other source of drug 204 and a pneumatic line 209 fordelivering gaseous drugs to electronic mixer 44. Filter 206 a in drugline 209 removes contaminants within the drug stream from drug source204. Pressure sensor 206 (which may be of a type known and currentlyavailable) in drug line 209 monitors the pressure in drug source 204generating a signal reflecting same and thereby indirectly measuring theamount of drug. Pressure sensor 206 is electronically coupled toelectronic controller 14 and forwards signals reflecting the measure ofpressure in the drug source to controller 14. As is described above inconnection with oxygen source pressure sensor 106 and in FIGS. 21A and23A, in a preferred embodiment controller 14 receives the signal fromsensor 206 and through software accesses stored data parametersreflecting safe and undesirable operating conditions of drug sourcepressure and conservatively controls drug delivery in accord with saidstored parameters.

The signal obtained from the drug source pressure sensor 206 can berelated to the user via display devices (e.g., 35, FIG. 2) in terms ofthe time remaining under present use so that the user can ascertain ifthe procedure can be completed. The user is immediately notified via analarm, display device or other suitable attention-commanding device ifthe pressure falls out of the normal operating conditions. Pressuregauges 208 visually display to the user the drug source pressureobtained by sensor 206. Pressure regulator 210, which may be of a knownsolenoid type currently available, enables the reduction of pressure indrug source 204 to a reasonable operating pressure to provide flow ofdrug to the patient. Check valve 212 in drug line 209 downstream ofregulator 210 prohibits backward flow of the patient's exhalations andensures that back-flow from the patient's exhalations does not damage orcontaminate regulator 210 and drug source 204. In systems where anin-house drug source 205 is used, remote check valve 214 ensures thatback-flow from the patient's exhalations does not damage or contaminatein-house drug source 205. Pressure relief valve 216 exhausts the drug tothe atmosphere if the pressure in drug line 209 exceeds safe operatingvalues pre-programmed into electronic controller 14.

To increase safety, the known pin indexed safety system (P.I.S.S.)and/or diameter indexed safety system (D.I.S.S.) may be used for all O₂source and line fittings where appropriate for tank and/or in-housesources. This ensures, for example, that oxygen source 104 is notmistakenly attached to the drug line 209 and vice versa.

FIG. 8 details a preferred electronic gas mixer system whichelectronically mixes gaseous drugs and oxygen so that the precise flowrate of gaseous drug and oxygen is delivered to the patient. The use ofthe electronic mixer system of this invention increases the operationalsafety of the apparatus of the invention because, as described below,the volume of drug delivery can be electronically controlled inclosed-loop fashion by currently available electronic flow controllerswhich include solenoid type valves which, in response to command signalsfrom electronic controller 14, halt or reduce the flow of drugs to thepatient in the event of an occurrence of unsafe patient or systemconditions. Specifically, pneumatic oxygen line 109 and drug line 209from analgesic source system 42 deliver gaseous drugs and oxygen tofilters 125 and 127 in lines 109 and 209, respectively, which filtercontaminants from lines 109 and 209. System state monitors, namely,pressure sensors 129, 131, monitor the oxygen and gaseous drug linepressures, respectively, and transmit signals reflecting said pressuresto electronic controller 14, which conservatively controls drug deliveryin accord with a stored data set containing parameters reflecting one ormore safe and undesirable system operation states as described above andin FIGS. 21A. and 23A. Also, if any of the pressures fall out of thenorm, electronic controller 14 immediately alerts the user, for example,by means of signaling an alarm device.

Electronic flow controllers 133, 135, which may be of a known typecurrently available including solenoid valves, are electronicallycoupled to and receive instruction signals from electronic controller 14which has been programmed with and/or calculates a desired flow rate ofoxygen and drug. Programmed flow rates may be those input by thephysician user employing traditional choices regarding drugadministration amounts and rates, including in IV embodiments, targetcontrolled infusion principles, among others. Calculated flow rates maybe arrived at through conservative decision-making software protocolsincluding comparison of actual patient physiological condition feedbackvalues with stored data representing safe and undesirable patientphysiological conditions. Drug delivery is effected at the ratescalculated in a closed, control-loop fashion (described in more detailbelow) by flow controllers 133, 135. Drug administration may be acombination of one or more physician inputs and/or electronic flow ratecalculations based on patient and system state parameters; flowcontrollers may respond to instruction signals initiated by electroniccontroller 14 or by the physician.

Flow controllers 133, 135 receive instruction signals from controller 14reflecting the electronic output of both system state monitors (such aspressure sensors 106, 206 described above) and patient state monitors.Flow controllers 133, 135, in response to instruction signals fromcontroller 14, may curtail or cease flow of drug delivery when systemstate and/or patient health monitors indicate to controller 14 thatfailures in the operation of care system 10 have occurred, that system10 is otherwise operating outside of an established safe state, or thata patient's physiological state (e.g., vital signs or consciousnesslevel) has deteriorated to an unsafe condition.

As the invention includes both intravenous and gaseous, among otherforms of drug delivery, such embodiments may also include knownelectronic flow controllers coupled to electronic controller 14 andresponsive to instruction signals from controller 14 reflecting bothpatient and system states.

Referring again to FIG. 8, solenoid valve 132 is electronically coupledto electronic controller 14 and must be activated by same before drugwill flow through line 209. In the event of system power failure, drugdelivery will be halted due to the fail-closed nature of solenoid valve132. This is described, for example, in FIG. 21A which shows that if asystem state monitor indicates power failure, alarm type “2” sounds toalert the nonanesthetist and drug delivery is halted (i.e., reduced to0%).

Moreover, pressure actuated valve 134 in drug line 209 responds to theamount of pressure in O₂ line 109 and permits flow of gaseous drug onlyif sufficient oxygen flows through oxygen line 109. Check valve 136 a indrug line 209 ensures that the flow of gaseous drug to manifold system46 is one-way and that there is no back-flow. Check valve 136 b inoxygen line 109 ensures one-way flow of O₂ to manifold system 46 with noback-flow.

In atmospheric air line 139, air inlet solenoid valve 137 iselectronically coupled to and activated by electronic controller 14 andif activated permits atmospheric air to be mixed with the oxygen gas bymeans of air ejector 138. Air ejector 138 injects a fixed ratio ofatmospheric air into oxygen line 109. Filter 128 removes contaminantsfrom air line 139 and check valve 136 c ensures one-way flow of air fromsolenoid valve 137 to ejector 138 with no back-flow.

Referring to FIG. 9A which details one embodiment of manifold system 46(FIG. 6), the drug/O₂ gas mixture from electronic mixer system 44 (FIG.6) enters manifold system 46 and flows into inspiratory plenum 150 fromwhich it proceeds through inspiratory line 151 to primary inspiratoryvalve (PIV) 152 and eventually to airway circuit 20 and mask 30 (FIG.1). Primary inspiratory valve 152 permits one-way flow of said gasmixture and ensures that exhaled gases from the patient do not enter theinspiratory side of manifold system 46 (FIG. 6), thereby guardingagainst possible contamination. Atmospheric air may be permitted toenter inspiratory line 151 through an inspiratory negative pressurerelief valve (INPRV) 154 which allows one-way flow of atmospheric air toreach the patient if a significant negative vacuum is drawn on theinspiratory side of manifold system 46 (e.g., the patient inhales andreceives no or insufficient oxygen). INPRV 154 thereby essentiallypermits air on demand by the patient. INPRV filter 153 removesparticulates which may be in air line 155 or present in the atmosphere.INPRV status sensor 156 (which may be of a known pressure, temperature,infra-red or other suitable type) monitors the extent of open/closestatus of INPRV 154 and generates a signal which is converted to anappropriate electronic (digital) signal and communicates the status ofINPRV 154 to electronic controller 14. During the exhalation phase ofthe patient's breathing cycle, inspiratory reservoir bag 149 collectsthe drug/O₂/air mixture which the patient will draw on the nextinhalation phase.

Still referring to FIG. 9A, pressure sensor 166 measures pressure inairway circuit 20 (FIG. 1) and is used to indicate airway flow, i.e., ifthe primary inspiratory valve (PIV) 152 or the primary expiratory valve(PEV) 168 is occluded. For example, if sensor 166 reads a high pressurethat indicates that PEV 168 is blocked, whereas a low pressure indicatesPIV 152 is blocked. Airway circuit 20 (FIG. 1) also contains a fractionof inspired oxygen (FIO₂) sensor 167 (which may be of a known typecurrently available) which measures the oxygen percentage of gascontained in the mixture delivered to the patient, and thus guardsagainst the possibility of delivering a hypoxic mixture to the patient(i.e., a drug/O₂ mixture that does not provide enough O₂ to thepatient). INPRV status sensor 156, pressure/airway flow sensor 166, andFIO₂ sensor 167 are electronically coupled to and provide electronicfeedback signals reflecting system state parameters to electroniccontroller 14. As described in FIGS. 21A and 23A, controller 14, throughsoftware and/or logic, effects a comparison of the signals generated bythese system monitors with a stored data set of system parametersestablished by setpoints and/or logic-type data reflecting safe andundesirable system operating states, and conservatively controls (e.g.,reduces or halts) drug delivery if the comparison determines that caresystem 10 is operating outside of a safe range.

Airway circuit and mask (20, FIG. 9) interface with the patient toprovide a closed circuit for the delivery of drug/O₂ gas mixture to thepatient. It should be recognized that embodiments of the subjectinvention in which the drugs are delivered in a form other thancompressed gas, such as intravenously or transdermally, may not includeface masks, airway circuit features and other aspects associated withdelivery of drugs in gaseous form. Where the drug is delivered ingaseous form and an airway circuit and face mask are employed, such facemask and attendant airway circuitry and other features such as thescavenging system may be in the form of that described in U.S. Pat. No.5,676,133 issued to Hickle et al. and entitled Expiratory ScavengingMethod and Apparatus and Oxygen Control System for Post-Anesthesia CarePatients. (With respect to such embodiments, the specification of Hickleet al. is incorporated herein by reference.)

In preferred embodiments the mask is disposable and contains means forsampling the CO₂ content of the patient's respiratory airstream and,optionally, means for also measuring the flow of the patient's airstreamand/or means for acoustical monitoring. The sampling of the CO₂ in thepatient's airstream may be done by means of a capnometer or a lumenmounted within the mask through a port in the mask, and placed close tothe patient's airway. A second lumen similarly mounted within the maskcould be used to measure the airflow in the patient's airstream. Thisairflow measurement could be accomplished by a variety of currentlyavailable devices, including for example, devices that measure thepressure drop in the airstream over a known resistance element andthereby calculate the airflow by known formula. The means for acousticalmonitoring may be a lumen placed within the mask with a microphoneaffixed within that lumen. The microphone would permit recording,transducing and playing out through an amplifier the audible sound ofthe patient's breathing. It is noted that the lumen for acousticalmonitoring could be a separate lumen or could be combined with the lumenfor calculating the flow of the patient's airstream. It is further notedthat it is important to place the lumens, especially the CO₂ samplinglumen, close to the patient's open airway and to ensure such lumensremain close to the patient's airway.

Referring again to FIG. 9A, primary expiratory valve (PEV) 168 inexpiratory line 172 ensures one-way flow of a patient's exhaled gases toscavenger pump system 48, thus, prohibiting any back-flow from gasesexhaled to the scavenger system from reaching the patient. Importantly,PEV 168 guards against the re-breathing of exhaled carbon dioxide. As iseasily seen, the manifold 46 and airway circuit 20 of a preferredembodiment of this invention permit one-way airway flow only. That is,unlike prior devices that employ circular airway circuits (which requireCO₂ absorbent material to permit re-breathing of exhaled air), there isno re-breathing of exhaled gases in this embodiment of the invention.

In the embodiment of the invention shown in FIG. 9A, expiratory positivepressure relief valve (EPPRV) 164 in expiratory line 172 allows exhaledgases to escape to the atmosphere if sufficient positive pressuredevelops on the expiratory side of the manifold system. This couldhappen, for example, if the patient is exhaling, but scavenger system 48(FIG. 6) is occluded or otherwise not working properly. EPPRV filter 175downstream of EPPRV 164 filters contaminants from the expiratory streamflowing through EPPRV 164 prior to the stream entering the atmosphere.Expiratory negative pressure relief valve (ENPRV) 178 is a one-way valvethat allows atmospheric air to be drawn into expiratory plenum 180 andthen on to scavenger system 48 if sufficient vacuum pressure is drawn onthe expiratory side of manifold system 46. This could happen, forexample, if the vacuum pump of scavenger system 48 is set too high orPEV 168 is blocked. Expiratory reservoir bag 177 collects exhaled gasesfrom the patient during exhalation via expiratory plenum 180. Thesegases will be exhausted by scavenger system 48 during the next patientinhalation phase. As is described in detail below, patient vital signmonitor, such as a capnometer 184, monitors the amount of CO₂ in thepatient's exhaled gases and provides electronic feedback signalsreflecting the level of CO₂ in the patient's exhalations to controller14. Other types of ventilatory monitors such as an airflow measure, IPGdevice or an acoustical monitor could also be used to provide electronicfeedback signals reflecting patient health parameters to controller 14.

In an alternative preferred embodiment shown in FIG. 9B, ENPRV 164,filter 175 and ENPRV 178 are eliminated. A long pipe or similar conduit175 a, interconnected with reservoir bag 177 and opening to atmosphericair, is substituted therefor. The elimination of the valves 164 and 175provides for a more cost efficient and simple system, while thesubstituting of the pipe 175 a still ensures that if the scavengersystem 48 is occluded, is set too high, is otherwise not working or ifPEV 168 is blocked, that there is still access to atmospheric air, andthe patient may breath into the room or air may come into the system. Ahighly compliant reservoir bag 179 also assists in catching excess flowof exhaled air. In this simplified embodiment, there are essentiallyonly three valves, PIV 152, PEV 168 and INPRV 154.

As is described above, system valves PIV 152 and PEV 168 ensure one-wayflow of inspired and expired gases. The patient cannot re-breatheexhaled gases and no contaminants are allowed to enter the sourcesystem. The valve system INPRV 154, EPPRV 164, and ENPRV 178 (or thealternate INPRV 154 and pipe) provides a system fail-safe. If analgesicsource system 42 (FIG. 6) or scavenging system 48 (FIG. 6) isfunctioning improperly, the valves will open and allow the patient tobreath without significant effort. The system state sensors 156, 166 and167 monitor system operation such as INPRV valve status, gas pressureand fraction of inspired oxygen, and electronically feed back signalsreflecting the operating status of those operations to microprocessorcontroller 14 to ensure safe operation of the apparatus.

It is noted that the valves and sensors between INPRV 154 and ENPRV 178in a preferred embodiment of manifold system 46 can be considered asystem state monitoring system because there are no valves controlled bythe software of electronic controller 14. At this point in the caresystem 10, the gas has already been mixed and the volume determined bythe flow controllers 133, 135 (FIG. 8). Manifold system 46 (FIG. 6)provides at least two basic services, sensor inputs for FiO₂ and CO₂(167, 184 of FIG. 9) and flow status derived from flow sensor 166 (FIG.9).

The determination of appropriate drug delivery/flow percentages bycontroller 14 can be accomplished through a variety of methods. Initialdrug administration amounts and rates may be selected and input by thephysician employing traditional methods. Physicians may also employpharmacokinetic/pharmacodynamic modeling to predict resulting drugconcentrations and their effect based on physician choices, but notpermit automatic changes to drug concentrations without instructionsfrom the physician. In intravenous embodiments known target-controlledinfusion techniques may be employed where the physician selects adesired (targeted) blood serum or brain effective site concentrationbased on such patient parameters as height, weight, gender and/or age.

During operation of the system when an internal or external eventoccurs, such as the activation of a system or patient health monitoralarm or a physician or patient request for increased drug, electroniccontroller 14 determines the desired amount of intravenous drug (orfractional amount of O₂, gaseous drug and air in the total gas flow) asthe function of such event. The actual IV drug concentrations (orgaseous drug/O₂/air fractions) are then calculated. These actualcalculated amounts will not always be the same as those requested (e.g.,by the user, patient or system) because of the often complexrelationship between drug or drug and gas mixtures. In sum, drug mixfractions are typically calculated when, for example, an alarm levelschange, alarm time-outs occur (e.g., there is no silencing of an initialalarm by the user), a user requests a change, the patient requests achange, when a procedure begins (system resorts to default values) andwhen a controller clock triggers.

In a preferred embodiment of the invention delivering gaseous drugs,flow controllers in mixer 44 (detailed in FIG. 8) determine the totalfresh gas flow (FGF) which is the sum of the volumes of each gas beingcontrolled, namely, the gaseous drug, oxygen and atmospheric air.Solenoid valves are opened proportionally to achieve the desired FGF andfractional amount of each gas. Flow controllers 133, 135 close thefeedback loop on the gas fractions by measuring the FiO₂ and fraction ofinspired gaseous drug in the manifold system 46 and adjusting the mixersolenoid valves accordingly.

In one aspect of the invention, the flow controllers 133, 135 match theFGF with patient minute ventilation rates. The minute ventilation rateis the volume of breath one inhales and then exhales (e.g., in cubiccentimeters or milliliters) in one minute. A patient's respiratoryphysiology is balanced at this minute ventilation. The care systemoptimizes FGF rates by matching gas delivery to patient minuteventilation rates. This conserves gas supplies, minimizes the release ofanesthesia gases into the operating environment, and helps balancerespiratory function. For example, if the FGF is less than the minuteventilation, INPRV 154 will open to supplement the air flow (INPRV 154being a mechanical system not under electronic control).

In an additional aspect of the invention, the care system will not onlymeasure and monitor minute ventilation as described above, but also“effective minute ventilation” and thereby improve the quantitativeinformation about patient physiology considered by the system.“Effective minute ventilation” is a term used herein to mean the amountof gas that is actually involved in respiratory gas exchange between thealveolar sacs of the lungs and the capillary blood surrounding thosesacs (as opposed to simply the volume of gas one inhales and thenexhales, “tidal volume”). This measure may be arrived at by subtractingthe volume of anatomical space imposed between the air source (e.g.,mouth) and the transfer of gas at the alveolar sacs (estimated from thepatient's height and weight), from the tidal volume of gas to arrive at“effective tidal volume.” The effective tidal volume is then multipliedby respiratory rate to arrive at “effective minute ventilation.”

FIG. 10A details manual bypass system 4 (FIG. 5) which is coupled tomanifold system 46. The bypass system 4 includes a self-inflatingresuscitation bag (SIRB) 19 a (also shown in FIG. 3B) which is a manualpump with which the user can provide air intermittently to the patientthrough a bypass air line 90. A quick disconnect type fitting 91 (suchas that disclosed in Hickle above) couples SIRB 19 a with manifoldsystem 46 and provides rapid attachment thereto. A manual flow controlvalve 92 opens or closes bypass air line 90. When line 90 is open,manual flow control valve 92 can be adjusted to provide the necessaryair flow. A flow meter 94 placed in bypass air line 90 provides a visualdisplay to the user of the status of air flowing through the bypass airline 90. The above-described manual bypass system 4 provides the patientwith manually-controlled flow of air and thus enables air delivery inthe case of an oxygen source system 144 (FIG. 7A) failure.

FIG. 10B details scavenger pump system 48 (FIG. 6) which is integratedinto the care system and vacuums exhaled gases from manifold system 46through a scavenging line 85. A filter 86 in scavenging line 85 removescontaminants from the gases which have been exhaled from the patient andwhich are flowing through the scavenger line 85. Pressure regulator 87receives the filtered gases and ensures that the vacuum pressure ismaintained in vacuum pump 95 downstream at a reasonable working level.Flow restrictor 88 sets the flow rate through the vacuum 95 for a givenvacuum pressure. Check valve 89 downstream of flow restrictor 88provides one-way flow of scavenged gases, and thus ensures thatback-flow does not inadvertently flow into scavenger system 48 from thevacuum pump 95 downstream. Vacuum pump 95 provides the vacuum pressurenecessary for scavenging of exhaled gases from the patient. The pump maybe of an electrical type that can be powered by office standard ACcurrent. As the vacuum pump is integrated into the care system, a wallvacuum source (such as that typically in an OR) is not required. Oncethe gases are vacuumed off, they are exhausted via exhaust hose 32 (FIG.3B) to an appropriate area. The benefit of scavenging system 48 is atleast two-fold in that the system helps assist the patient in the workof breathing and work environment safety is increased.

In a preferred embodiment, an emesis aspirator 19 (FIG. 3B) isintegrated into system 10 and may be stored within housing 15. Emesisaspirator 19 is a manually operated device used to suction a patient'sairway in the event of vomiting. Emesis aspirator 19 does not require anexternal vacuum source (e.g., wall suctioning) or electrical power foroperation.

To enhance the safety of the invention, housing 15 may include structureintegrated adjacent or otherwise near where emesis aspirator 19 isstored within housing 15 (FIG. 3B) to hold and prominently displaycontainers of drugs capable of reversing the effects of varioussedatives/analgesics. These “reversal drugs,” such as naloxone,remazicon and others may be immediately administered to the patient inthe event of an overdose of sedative, analgesic and/or amnestic.

Referring to FIG. 11, a preferred embodiment of the invention includesan integrated patient interface system which combines one or morepatient health monitors 252 (additional health monitors to those shownare also contemplated by the invention) with additional automatedpatient feedback devices including a patient drug dosage increase ordecrease request device 254 and an automated consciousness query system256 for monitoring a patient's level of consciousness. These healthmonitors 252 and automated patient feedback devices 254, 256 areelectronically coupled to electronic controller 14 via leads (e.g., 50,FIG. 2) and provide electronic feedback values (signals) representingthe patient's physiological condition to controller 14. Generally, ifany monitored patient parameter falls outside a normal range (which maybe preset by the user or otherwise preprogrammed and stored in memorydevice as described above), the nonanesthetist is immediately alerted,for example, by an alarm, display or other attention-commanding device.The information obtained from patient health monitors 252 is displayedon a display device 35 (FIG. 2), in, for example, continuous wave formor numerics on LEDs, thus allowing the procedural physician toimmediately gain useful information by reviewing the display device.Preferred embodiments of displays contemplated by the invention aredescribed in more detail below.

A preferred embodiment of one aspect of the invention integrates drugdelivery with one or more basic patient monitoring systems. Thesesystems interface with the patient and obtain electronic feedbackinformation regarding the patient's physiological condition. Referringto FIG. 11, a first patient monitoring system includes one or morepatient health monitors 252 which monitor a patient's physiologicalconditions. Such monitors can include a known pulse oximeter 258 (e.g.,an Ohmeda 724) which measures a patient's arterial oxygen saturation andheart rate via an infra-red diffusion sensor; a known capnometer 184(e.g., a Nihon Kohden Sj5i2) which measures the carbon dioxide levels ina patient's inhalation/exhalation stream via a carbon dioxide sensor andalso measures respiration rate; and a known non-invasive blood pressuremonitor 262 (e.g., a Criticon First BP) which measures a patient'ssystolic, diastolic and mean arterial blood pressure and heart rate bymeans of an inflatable cuff and air pump. A care system constructed inaccordance with this invention may include one or more of such patienthealth monitors. Additional integrated patient health monitors may alsobe included, such as, for example, a measure of the flow in a patient'sairstream, IPG ventilatory monitoring, a standard electrocardiogram(EKG) which monitors the electrical activity in a patient's cardiaccycle, an electroencephalograph (EEG) which measures the electricalactivity of a patient's brain, and an acoustical monitor whose audiosignals may be processed and provided to controller 14 and amplified andplayed audibly.

A second patient monitoring system monitors a patient's level ofconsciousness by means of an automated consciousness query (ACQ) system256 in accordance with the invention. ACQ system 256 comprises a queryinitiate device 264 and a query response device 266. ACQ system 256operates by obtaining the patient's attention with query initiate device264 and commanding the patient to activate query response device 266.Query initiate device 264 may be any type of a stimulus such as aspeaker which provides an auditory command to the patient to activatequery response device 266 and/or a vibrating mechanism which cues thepatient to activate query response device 266. The automatedpressurization of the blood pressure cuff employed in the patient healthmonitoring system may also be used as a stimulus. Query response device266 can take the form of, for example, a toggle or rocker switch or adepressible button or other moveable member hand held or otherwiseaccessible to the patient so that the member can be moved or depressedby the patient upon the patient's receiving the auditory or otherinstruction to respond. In a preferred embodiment, the query system hasmultiple levels of auditory stimulation and/or vibratory or othersensory stimulation to command the patient to respond to the query. Forexample, an auditory stimulus would increase in loudness or urgency if apatient does not respond immediately or a vibratory stimulus may beincreased in intensity.

After the query is initiated, ACQ system 256 generates signals toreflect the amount of time it took for the patient to activate responsedevice 266 in response to query initiate device 264 (i.e., this amountof time is sometimes referred to as the “latency period”). ACQ system256 is electronically coupled to electronic controller 14 and thesignals generated by ACQ system 256 are suitably converted (e.g.,employing an A-D converter) and thereby provided to controller 14. Ifthe latency period is determined by controller 14, which employssoftware to compare the actual latency period with stored safety dataset parameters reflecting safe and undesirable latency periodparameters, to be outside of a safe range, the physician is notified,for example, by means of an alarm or other attention-commanding device.If no action is taken by the physician within a pre-set time period,controller 14 commands the decrease in level ofsedation/analgesia/amnesia by control and operation on electronic flowcontrollers 133, 135 of FIG. 8. The values of the signals reflecting thelatency period are displayed on display device 35 (or on LED deviceslocated on housing 15 or on remote control device 45, FIG. 1) and thephysician may thus increase or decrease drug delivery based on thelatency period.

The patient interface system of FIG. 11 also includes a drug dosagerequest device 254 which allows the patient direct control of drugdosage. This is accomplished by the patient activating a switch orbutton to request electronic controller 14 to command the increase ordecrease in the amount of drug he or she is receiving. For example, if apatient experiences increased pain he or she may activate the increaseportion of the switch of device 254, whereas, if a patient begins tofeel nauseous, disoriented or otherwise uncomfortable, he or she mayrequest a decrease in drug dosage. In embodiments where drug delivery isintravenous, such delivery can be by continuous infusion or bolus. Afeedback signal from device 254 representing the patient's increase ordecrease in drug dosage request is electronically communicated tocontroller 14 which employs conservative, decision-making software,including comparison of monitored patient conditions with stored safetyparameters reflecting patient physiological conditions, to effect safe,optimized drug delivery in response to patient requests. The amount ofincrease or decrease administered by controller 14 can be pre-set by thephysician through user access devices such as keyboard 230, FIG. 2. Forexample, where the drug being delivered is nitrous oxide, the approvedincrease or decrease may be in increments of +10%. When not activated bythe patient, drug request device 254 remains in a neutral position. Theinvention thus integrates and correlates patient-controlled drugdelivery with electronic monitoring of patient physiological conditions.

In an alternative embodiment, the physician is notified via userinterface system 16 (display device 30 or LEDs remote control device45), FIG. 1 of the patient request to increase or decrease drug dosageand can approve the requested increase or decrease taking into accountthe patient's present vital signs and other monitored physiologicalconditions, including consciousness level status as obtained from-thevarious patient interface system monitors 252, 256 (FIG. 11).

In a preferred embodiment of the invention, the patient controlled drugdosage request system 254 has lock-out capabilities that prevent patientself-administration of drugs under certain circumstances. For example,access to self-administration will be prevented by electronic controller14 under circumstances where patient physiology parameters or machinestate parameters are or are predicted to be outside of the stored safetydata set parameters. Access to self-administration of drugs could alsobe inhibited at certain target levels or predicted target levels ofdrugs or combined levels of drugs. For example, if it were predictedthat the combined effect of requested drugs would be too great, drugdelivery in response to patient requests would be prohibited. It isnoted that such predictive effects of drugs could be determined throughthe use of various mathematical modeling, expert system type analysis orneural networks, among other applications. In short, the invention isdesigned to dynamically change drug administration and amount variablesas a function of patient physiology, care system state and predictiveelements of patient physiology.

Additionally, it is contemplated that patient self-administration ofdrugs could be prohibited at times when drug levels are changingrapidly. For example, if a patient is experiencing pain and that isapparent to the physician, the physician may increase the target levelof drug while at the same time the patient requests additional drug. Thesubject invention will sequentially address the physician and patientrequests for drug increases and will lock out any patient-requestedincreases that are beyond programmed parameters.

In an additional aspect of the invention, a patient may be stimulated orreminded to administer drugs based on electronic feedback from thepatient physiology monitoring systems. For example, if there is anunderdosing of analgesics and the patient is suffering pain evidenced bya high respiratory rate or high blood pressure reflected in electronicfeedbacks to the electronic controller, the controller can prompt thepatient to self-administer an increase in drugs. This could beaccomplished by, for example, an audio suggestion in the patient's ear.Thus, it is contemplated that the invention will have an anticipatoryfunction where it will anticipate the patient's needs for increaseddrugs.

In a preferred embodiment of the invention, one or more patient vitalsign monitoring devices 252, ACQ system devices 256, and a drug dosagerequest device 254 are mechanically integrated in a cradle or gauntletdevice 55 (FIG. 2) constructed to accommodate and otherwise fit around apatient's hand and wrist. FIG. 2 shows generally hand cradle device 55electronically coupled by lead 50 to care system 10. One embodiment of ahand cradle device in accordance with this invention is shown in moredetail in FIGS. 12A and 12B.

FIG. 12A shows blood pressure cuff 301 capable of being wrapped around apatient's wrist and affixed to itself such that it can be held in place.Cuff 301 is affixed to palm support portion 303. Alternatively, the cuffmay be separated from palm support portion 303 and placed on the upperarm at the physician's discretion. A recessed, generally elliptical orrounded portion 305 is supported by the top edge of palm support portion303 and is capable of receiving and supporting the bottom surface of apatient's thumb. Depressible query response switch 307 is located withinthumb support portion 305 such that switch 307 is capable of beingdepressed by the patient's thumb. The thumb support portion 305 may beconstructed so as to have a housing, frame, raised walls or other guideso that a patient's thumb may more easily be guided to depress or movebuttons or switches within portion 305 (here, switch 307), or so thatany significant patient thumb movement toward the switch will activatesame. Supporting thumb support portion 305 and abutting palm portion 303is finger support portion 309 for receiving in a wrapable fashion thepatient's fingers. Drug dosage request switch 311 is integrated intofinger support portion 309 and is in the form of a rocker switch wherebydepressing the top portion 310 a of said switch will effect an increasein the delivery of sedative, analgesic and/or amnestic whereasdepressing the bottom portion 310 b of said rocker switch will effect adecrease in drug delivery at an appropriate set percentage (e.g., ±10%,FIG. 12B). Rocker switch 311 is constructed so as to remain in a neutralposition when not being actuated by the patient.

FIGS. 13A and 13B show an additional embodiment of the hand cradledevice of this invention. Specifically, a pulse oximetry sensor 314 ismechanically affixed to and electronically coupled to hand cradle device55 abutting the upper end of finger support portion 309, and beinggenerally planar vis-a-vis the outer edge of thumb support portion 305.Pulse oximeter 314 is constructed as a clip which can be placed on apatient's finger. The transmitter and receiver portions of sensor 314are contained in the opposite sides 315 a, 315 b (FIG. 13B) of thefinger clip 314 such that when placed on a finger, infra-red radiationtravels through the finger; through spectral analysis the percentage ofoxygenated hemoglobin molecules is determined. In this embodiment ofhand cradle device 55 the query initiate device 313 is in the form of asmall vibrator located in palm support portion 303. Alternatively, toenhance patient attentativeness to the query initiate device and toincrease patient accuracy in depressing the response switch, thevibrator may be located adjacent the query response switch 307 or, inthe embodiment of FIG. 14A, adjacent response switch 407.

In an alternative embodiment of hand cradle device 55, now referring toFIGS. 14A and 14B, drug dosage request device 409 is located withinthumb portion 405 and is in the form of a slidable member 409 whereinsliding member 409 forward effects an increase in analgesic dosage andsliding portion 409 backward effects a decrease in analgesic dosage(FIG. 14B). In this embodiment of the invention, query response device407 is a depressible portion integrated within finger support portion409.

All embodiments of hand cradle device 55 are constructed so as to beambidextrous in nature, namely, they accommodate and are workable by apatient's right or left hand. For example, in FIGS. 12A and 13A, asecond query response switch 307 b is located within a symmetricallyopposed thumb portion 305 b affixed to the opposite end of fingerportion 309. Similarly the device of FIG. 14A is also constructed with asymmetrically opposed thumb portion 405 b and drug dosage request device409 b. The pulse oximeter clip 314 is affixed to finger support portion309 so as to be mechanically and electronically quick releasable topermit reversibility when used on the opposite hand. It should also berecognized that the pulse oximeter clip 314 may be tethered to handcradle device 55 rather than mechanically affixed thereto, or bloodpressure cuff 301 and oximeter clip 314 may be mechanically separatefrom cradle device 55 and electronically coupled to controller 14 withflexible leads.

Referring to FIG. 15, an additional alternative embodiment of theinvention is shown in which hand cradle device 55 includes mechanicallyintegrated blood pressure cuff 301, query response device 307 andanalgesic request device 309 similar to that described above. Thisembodiment, however, includes an ear clip device 450 capable of beingclipped to the lobe of a patient's ear and being electronically coupledto electronic controller 14 via lead 456. Referring additionally to FIG.16, ear clip 450 comprises a query initiate device 452 in the form of aspeaker which provides an audible command to patient to activate theresponse switch. Such speaker may also command a patient toself-administer drugs or play music to a patient during a procedure.Pulse oximeter 454 is a clip capable of being affixed to a patient's earlobe. One side of the clip being a transmitter and the other side of theclip being a receiver to effect the infra-red spectral analysis of thelevel of oxygen saturation in the patient's blood.

In an additional aspect of the invention, it is contemplated that thecare system's automated monitoring of one patient health conditions issynchronized with the monitoring of one or more other patient healthconditions. For example, in a preferred embodiment, if the controller14, receives low O₂ saturation, low heart rate or a low perfusion indexfeedback information from the pulse oximeter (e.g., the actual parameterreceived is in the undesirable range of the stored safety data set forthose parameters), such feedback will trigger controller 14 toautomatically inflate the blood pressure cuff and check the patient'sblood pressure. (This is because low O₂ saturation can be caused by lowblood pressure; and low heart rate can cause low blood pressure and viceversa, etc.) Therefore, under normal operating conditions the preferredembodiment of the invention will automatically check the patient bloodpressure every 3 to 5 minutes, and whenever there is a change in otherpatient parameters such as blood O₂ saturation or heart rate. In anotherexample, the electronic checking of blood pressure is synchronized withthe automated consciousness query because the activation of the cuff mayarouse a patient and affect query response times. Thus the inventioncontemplates an “orthogonal redundancy” among patient health monitors toensure maximum safety and effectiveness.

As described above, one aspect of a preferred embodiment of theinvention includes the electronic management of drug delivery viasoftware/logic controlled electronic controller 14 to integrate andcorrelate drug delivery with electronic feedback signals from systemmonitors, one or more patient monitor/interface devices and/or userinterface devices. Specifically, electronic signal values are obtainedfrom care system state monitors; from patient monitor/interface devices(which can include one or more vital sign or other patient healthmonitors 252, ACQ system 256, and/or patient drug dosage request device254, FIG. 11); and in some instances from one or more user interfacedevices. All are electronically coupled to, through standard A-Dconverters where appropriate, electronic controller 14. The controller14 receives the feedback signal values and, via software and programmedlogic, effects a comparison of these values representing the patient'smonitored physiological conditions with known stored data parametersrepresenting safe and undesirable patient physiological conditions (asafety data set). Controller 14 then generates an instruction inresponse thereto to maintain or decrease the level of sedation,analgesia, and/or amnesia being provided to the conscious patientthereby managing and correlating drug delivery to safe, cost-effectiveand optimized values (FIG. 2B. Controller 14 is operatively,electronically coupled to electronic flow controllers 133, 135 (FIG. 8)of electronic mixer 44 which (via solenoid valves) adjust flow ofgaseous drug and O₂ in a closed-loop fashion as described above. Inintravenous embodiments such flow controllers would adjust the flow ofone or more combination of IV drugs. It should be recognized that theelectronic values provided to microprocessor controller 14 to effectmanagement and correlation of drug delivery, could include one or moresignals representing patient vital signs and other health conditionssuch as pulse oximetry, without necessarily including signal(s)representing level of patient consciousness, and vice versa.

As also indicated above, the software effecting electronic management ofdrug delivery by controller 14 employs “conservative decision-making” or“negative feedback” principles. This means, for example, that theelectronic management of drug delivery essentially only effects anoverall maintenance or decrease in drug delivery (and does not increasedrugs to achieve overall increased sedation/analgesia). For example, ifACQ system 256 (FIG. 11) indicates a latency period outside of anacceptable range, controller 14 may instruct electronic flow controller133 (FIG. 8) to increase the flow of oxygen and/or instruct flowcontroller 135 to decrease the flow of gaseous drug to manifold system48.

In another example of such electronic management of drug delivery byconservative decision-making principles, if ACQ system 256 (FIG. 11)indicates a latency period in response to a patient query given every 3minutes outside of an acceptable range, electronic controller 14 mayimmediately cease drug delivery, but at the same time, increase thefrequency of times that the patient is queried, e.g., to every 15seconds. When the patient does respond to the query, the drug deliveryis reinitiated, but at a lower overall dose such as 20% less than theoriginal concentration of drug that had been provided.

A further example of the invention's electronic management of drugdelivery through conservative, decision-making software instructionemploys known target-controlled infusion software routines to calculatean appropriate dosage of IV drug based on patient physical parameterssuch as age, gender, body weight, height, etc. Here, a practitionerprovides the patient physiological parameters through the user interfacesystem, the electronic controller 14 calculates the appropriate drugdosage based on those parameters, and drug delivery begins, for example,as a bolus and is then brought to the pre-calculated target level ofinfusion. If later there is a significant change in a patient monitoredparameter, e.g., pulse oximetry or latency period falls outside of adesired range, controller 14 effects a decrease in overall drug deliveryas described above.

One concern that the invention addresses with respect to the targetcontrolled infusion of IV drugs is the nature and speed at which thecare system reaches the steady state target level of drug. For example,an important consideration for the physician is, once drugadministration begins, when is the patient sufficiently medicated (e.g.,sedated or anesthetized), so that the physician can begin the procedure.It is frequently desirable that the patient reach the steady statetarget level of drug as rapidly as possible so that the procedure canbegin as soon as possible. It has been determined that one way ofreaching a suitable level of drug effectiveness quickly is to initiallyovershoot the ultimate steady state target drug level. This shortens thetime between the beginning of drug delivery and the onset of clinicaldrug effectiveness so that the procedure may begin. Typically, predictedtarget levels have an error of plus or minus 20%, therefore, oneapproach of reaching the clinical effectiveness state quickly is toattempt to reach at least 80% of the ultimate target level, butinitially overshoot that 80% level by giving a 15% additional increaseof drug infusion beyond the 80% target. One method of accomplishing thisis to use currently available PDI controllers which employ an errorstate (here the difference between predicted drug levels in the bloodstream and the target level) to arrive at an infusion rate. Othercontrol systems, however, that allow some initial overshoot of thetarget blood level of the drug to get to a clinical effectiveness levelquicker would also be appropriate.

FIG. 17 is a schematic of an alternative embodiment of an apparatusconstructed in accordance with the invention which is particularlysuitable for remote medical care locations and home care-type settingsfor indications such as post-operative or other post-procedural painand/or discomfort, including, for example, nausea secondary to oncologychemotherapy. In this embodiment, drug source system 442 delivers drugsto the patient (which may be drugs such as propofol, morphine,remifentanil and others) intravenously by, for example, use of a knownsyringe pump-type device capable of being worn or otherwise affixed tothe patient, or delivers such drugs transdermally by, for example, useof known ion transfer-type devices, among others. The drug delivery maybe continuous or by drug bolus and without an integrated supply of O₂.If necessary, oxygen may be supplied to the patient from separate tanksor an in-house, on-site oxygen source. The resulting apparatus issimplified—there is no requirement for an integrated O₂ source,electronic mixer, manifold, or the airway circuit and face mask devicesdescribed above.

One or more patient health monitors 412 such as known pulse oximeters,blood pressure cuffs, CO₂ end tidal monitors, EKG, and/or consciousnessmonitors, or other monitors such as those indicated herein, monitor thepatient's physiological condition. Drug dosage may be pre-set by aphysician prior to or during application of drug delivery and/or alsopatient controlled thereafter by means of a patient drug dosage increaseor decrease request devices generally of the type of that describedabove. It should also be understood that the intravenous delivery ofdrugs may be by continuous infusion, target-controlled infusion, purebolus, patient-elected bolus or combinations thereof.

Still referring to FIG. 17, electronic management of drug delivery inthis embodiment of the invention is provided by electronic controller414 which may be of a type described above. Controller 414 employsconservative decision-making software and/or logic devices to integrateand correlate drug delivery by drug source system 442 (which may includeknown solenoid type or other electronic flow controllers) withelectronic feedback values from one or more patient health monitors 412.The values (signals) from patient health monitors 412 represent one ormore actual patient monitored physiological conditions. Controller 414,through software employing comparison protocols such as those describedherein, accesses stored safety data set 410 which contains datareflecting safe and undesirable patient physiological conditions, andcompares the signals reflecting actual patient monitored conditions withsame. As described above, safety data set 410 may be stored in a memorydevice such as an EPROM. Based on the result of the comparison,controller 414 either instructs no change in drug delivery or generatesa signal instructing the drug flow controllers of drug source system 442to manage application of the drug to safe, optimized levels.

In certain aspects of the invention, controller 414 may also access,through software, pre-set parameters stored in a memory devicerepresenting initial or target drug dosages and lock-outs of patientdrug administration requests as described above. In these circumstances,instruction signals generated by controller 414 would also account forand control drug delivery in accord with these pre-set parameters.

This embodiment of the invention would also typically include systemstate monitors, such as electronic sensors which indicate whether poweris being supplied to the system or which measure the flow of drugs beingdelivered. Such system state monitors are electronically coupled tocontroller 414 and provide feedback signals to same—the control of drugdelivery by controller 414 electronically coupled to drug source system442 in response to said feedback signals is similar to that as describedherein with respect to other embodiments.

In another aspect of the invention, electronic controller 414 is locatedon a remote computer system and electronically manages on-site drugdelivery integrating and correlating same with on-site monitoring ofpatient physiological conditions and care system states as describedabove, but here with instructions signals generated from a remotelocation. It is contemplated that controller 414 may, in someembodiments, effect transmission via modem or electronic pager orcellular-type or other wired or wireless technologies of electronicalarm alerts to remote locations if a monitored patient parameter suchas the percentage of oxygen absorbed into the blood (S_(p)O₂) fallsoutside of a safe established value or range of values as established bythe stored safety data set. Such remote locations could thereby summonan ambulance or other trained caregiver to respond to the alarm alert.

FIG. 18 details the user interface system of a preferred embodiment ofthe invention. This system enables the physician to safely andefficaciously deliver one or more of sedation, analgesia or amnesia to apatient while concurrently performing multiple tasks. The user interfacepermits the physician to interact with the care system and informs theuser of the patient's and system's status in passive display devices anda variety of active audio/visual alarms thereby enhancing the safety andenabling immediate response time (including the “conservative”responses, e.g., detailed drug delivery discussed above) to abnormalsituations.

Specifically, a keypad and/or touch screen 230 (FIGS. 2 and 18) allowsthe physician to interact with electronic controller 14, inputtingpatient background and setting drug delivery and oxygen levels. A remotecontrol device 45 (FIGS. 1 and 18) provides the physician with remoteinteraction with the care system 10 allowing him or her to remotelycontrol the functions of the system. Remote control device 45 may beremovably integrated into the top surface of housing 15 and capable ofbeing clipped onto material close to the physician and/or patient. Inone aspect of the invention, the remote control device 45 itselfcontains display devices such as LEDs to advise the physician of patientand system parameters. A panic switch 232 (FIG. 18), which may beon-board housing 15 (FIG. 1) or contained in remote control device 45and electronically coupled to controller 14 allows the physician to shutdown care system 10 and maintains it in a safe state pre-programmed intocontroller 14.

Visual display devices 234 (FIG. 2, 35) display actual and predictive ortarget patient and system parameters and the overall operation status ofthe care system.

One version of a preferred embodiment of visual display 234 is shown inFIG. 22. The display 2230 includes a first portion of the display 2234which is devoted to displaying to the user the current status of thesystem operation and monitored patient conditions, including the statusof any alarm caused by a change in monitored system or patientcondition. For example, if a patient's timed response to a consciousnessquery (latency period) is outside an established range and an alarm isthus activated, that query latency period is displayed in this firstportion 2234 of the visual display, thereby enabling the physician toimmediately understand the cause of the alarm.

The visual display device 2230 of this embodiment also includes a secondportion of the display 2236 which is devoted to displaying the actionstaken or soon to be taken by the care system. For example, if inresponse to an alarm indicating a latency period outside of anestablished safe range the apparatus will decrease the flow of drug tothe patient, this second portion 2236 displays the percentage decreasein drug dosage to be effected.

Visual display 2230 facilitates the physician's interaction with theapparatus by walking the physician through various system operationsoftware subprograms. Such subprograms may include system start-up wherea variety of system self-checks are run to ensure that the system isfully functional; and a patient set-up. To begin the procedure, the caresystem monitors are placed on the patient and the physician activatesthe system by turning it on and entering a user ID (it is contemplatedthat such user ID would only be issued to physicians who are trained andcredentialed). Next, the visual display would prompt the physician tobegin a pre-op assessment, including inputting patient ID informationand taking a patient history and/or physical. In the pre-op assessment,the physician poses to the patient a series of questions aimed atdetermining appropriate drug dosage amounts (such as age, weight, heightand gender), including factors indicative of illness or high sensitivityto drugs. The responses to such questions would be inputted into thecare system and employed by the system to assist the physician inselecting the appropriate dose amount. For example, the care system maymake available to the physician one range of dosage units for a healthyperson and a narrower range of dosage units for a sick or older person.The physician would have to make an explicit decision to go above therecommended range.

In addition to the pre-op assessment performed by the physiciandescribed above, it is also contemplated that the care system is capableof performing an automated pre-op assessment of the patient'sphysiology. For example, with the monitors in place, the care systemwill assess such parameters as the oxygenation function of the patient'slungs and/or the ventilatory function of the patient's lungs. Theoxygenation function could be determined, for example, by consideringthe A-a gradient, namely, the alveolar or lung level of oxygen comparedto the arteriolar or blood level of oxygen. The ventilatory function ofthe lungs could be determined from pulmonary function tests (PFTs),among other things, which are measurements of the amount of air and thepressure at which that air is moved in and out of the lungs with eachbreath or on a minute basis. (It is contemplated that these assessmentsare performed before the procedure begins and during the procedure as adynamic intra-operative assessment as well.) Also during the pre-op (oras a continuous intra-operative) assessment, heart function may beassessed by viewing the output of an EKG to determine whether there isevidence of ischemia or arrhythmias. Alternatively, automatedalgorhythms could be applied to the EKG signals to diagnose ischemia orarrhythmias. Additional automated patient health assessments could alsobe made.

During patient set-up, current patient and system parameters may also beassessed and displayed, and the consciousness-query system and patientdrug increase/decrease system tested and baselined. A set drugsubprogram allow for the selection of drugs and/or mixture of drugs (ordrug, oxygen and air), allows for picking target levels of drugs, and/orpermits enabling of the patient's self-administration of drugs withincertain ranges. The invention also contemplates during the pre-opassessment determining a sedation threshold limit for the given patientin the unstimulated state. This could be done as a manual check, i.e.,by simply turning up the drug levels and watching the patient manuallyor the procedure could be automated where the drugs are increased andthe safety set parameters such as those for latency (consciousnessqueries) are tested as the concentration at the drug effect site isincreased.

The system and patient status and system action may be displayed during,for example, a sedation subprogram. Visual display device 2230 mayinclude graphical and numeric representations of patient monitoredconditions such as patient respiratory and ventilatory status,consciousness, blood O₂ saturation, heart rate and blood pressure(2238); an indication of elapsed time from the start of drug delivery(2239); drug and/or O₂ concentrations (2241); and indications of patientrequests for increases or decreases in drug (2243). The actual fractionof inspired oxygen calculated may also be displayed. Command “buttons”are included to mute alarms (2240), change concentration of drugdelivered (2242), turn on or off the mixing of an oxygen stream withatmospheric air (2244), and to turn on or off or make other changes tothe automated consciousness query system (2246). Command buttons mayalso be included to place the apparatus in a “recovery” mode once theprocedure is completed (patient parameters are monitored, but drugdelivery is disabled) (2248), and to end the case and start a new case(2250) or shut-down the system.

An alternate version of a preferred embodiment of the visual displayportion of the invention is shown in FIG. 22A. Portions 2202, 2204, 2206and 2208 of display device 2200 show current patient O₂ saturation,blood pressure, heart rate, and end tidal CO₂ levels, respectively.These portions displaying patient physiological state are uniquely colorcoded. Smart alarm box portion 2212 which may be coded in an attentiongetting color such as red, displays to the physician the particularalarm that has sounded. For example, if the patient O₂ blood saturationlevel falls below safe levels, the O₂ saturation alarm will sound andthe O₂ saturation level will appear in smart alarm box portion 2212where it can be easily seen by the physician. In short, whateverparameter has alarmed is moved to the smart alarm box portion; thespecific alarm indicator is moved to the same place every time an alarmsounds. Also, the level of criticality of the alarm which, as describedbelow, in a preferred embodiment may be indicated by either yellow orred color, is displayed in the patient physiological parameter portionof the display. For example, if a red level O₂ saturation alarm sounds,the background portion of the O₂ saturation portion 2202 will appear inred.

Portion 2214 of display 2200 shows the past, present and predictedlevels (2215) of drug administration (the drug levels shown in FIG. 22Aare the levels of nitrous oxide remifentanil and propofol). In apreferred embodiment target controlled infusion past, present andpredicted levels are shown graphically beginning with the past thirtyminutes and going thirty minutes into the future. The invention alsocontemplates bracketing a range of accuracy of target controlledinfusion levels (not shown).

Display portions 2220 and 2224 depict graphical representations ofpatient health parameters such as the A-a gradient (oxygenationfunction) for the lungs, the results of pulmonary function tests,electrocardiogram, blood O₂saturation, among others.

In another aspect of the invention, visual display 35 (FIG. 1) may beremovably integrated into the top surface of housing 15 and capable ofbeing removed from housing 15 and affixed to a frame near the patient,such as a gurney rail or examination table. Alternatively, or inaddition thereto, a heads-up type visual display device is provided tofacilitate a nonanesthetist's involvement in the medical or surgicalprocedure while simultaneously being able to view the status of systemand patient monitored values and the details of alarm states. In thiscase, the display device is miniaturized and mounted onto a wearableheadset or eyeglass-type mount or mounted on an easily viewed walldisplay.

Referring again to FIG. 18, in a preferred embodiment, audible alarms236 alert the physician when patient or system parameters are outside ofthe normal range. In preferred embodiments, the alarms may be two orthree stages with different tones to indicate different levels ofconcern or criticality. As is described above, when an alarm sounds, theuser is able to immediately view the cause of the alarm because thesmart alarm box portion 2212 of the visual display 2200 shows the valueof the monitored system or patient parameter that caused the alarm toactivate.

FIG. 21 shows examples of drug delivery management protocols forthree-stage alarms responsive to patient monitors, namely, alarms “1,”“2” and “3,” in accordance with a preferred embodiment of one aspect ofthe invention. These alarms may have different tones or other indicatorsto denote different levels of concern or criticality. The dataflowdiagram of FIG. 23 depicts one example of the steps performed by thedrug delivery managing software or logic for one such protocol, namely,one where electronic controller 14 described above receives anelectronic feedback signal from a pulse oximeter monitoring the actualamount of oxygen saturation in a patient's blood (the value indicated by“SpO₂”). As is shown, the SpO₂ value is compared with stored safety dataset 220 containing a parameter value or range of parameters valuesreflecting safe and undesirable patient blood oxygen saturationconditions. If the SpO₂ value is greater than or equal to storedparameter 90%, no alarm sounds and no adjustment to drug delivery iseffected (221 a). If the SpO₂ value is less than 90%, but greater than85% (221 b), alarm 1 sounds for 15 seconds (222). If alarm 1 is silencedmanually (222 a), no further action is taken by the system. If alarm 1is not silenced, the amount of drug being delivered (in this examplegaseous N₂O) is reduced to the lesser of a concentration of 45% or thecurrent concentration minus 10% (223). The software/logic procedurewould operate in a similar fashion for intravenous and nebulized formsof drugs and the instructions provided (e.g., as in 223) would bespecified for safe dosages of such drugs.

Further, if the value of oxygen saturation (SpO₂) is less than 85%, butgreater than or equal to 80% (221 c), alarm 2 sounds and the amount ofN₂O being delivered is immediately reduced to the lesser of aconcentration of 45% or the current concentration minus 10% (224). Ifthe feedback value SpO₂ from the pulse oximeter indicates that theoxygen saturation in the blood is less than 80%, alarm 3 sounds and theamount of N₂O being delivered would be immediately reduced to 0% (225).

Similar protocols are described in FIG. 21 for electronic feedbacksignals from patient health monitors indicating pulse rate, amount ofcarbon dioxide in a patient's end tidal exhalations, respiration rate,systolic blood pressure, and feedback from the automated consciousnessmonitoring system constructed in accordance with the invention. Theseprotocols are effected with software (and/or logic) operating in similarfashion to that described in the dataflow diagram of FIG. 23. That is,the protocol shown in FIG. 23 is one example employing one patientmonitored parameter, but the operation of the invention would be similarto effect the remaining protocols of FIG. 21.

It should be understood that the system responses to alarms (describedabove in terms of decreases or cessation of drug concentration) couldalso include institution and/or increases in administration of oxygen inaccord with patient and system state parameters as described above. Incircumstances where drugs are halted and pure oxygen (or an O₂atmospheric mix) is provided, e.g., where feedback signals indicate thepatient has a low blood O₂ saturation, a preferred system is designed tooperate in a LIFO (“last-in-first-out”) manner. This means that whencontroller 14 receives feedback signaling an adverse patient or machinestate and instructs flow controllers to turn on the oxygen, the verynext breath the patient takes will be of pure O₂ (and/or atmosphericair) rather than of a drug/air mixture. This may be accomplished, forexample, by supplying O₂ for air directly to PIV 152 (FIG. 9A) andbypassing reservoir bag 149.

FIG. 21A shows examples of drug delivery management protocols fortwo-stage alarms responsive to system state monitors, namely, alarms “1”and “2,” in accordance with a preferred embodiment of one aspect of theinvention. The alarms may have different tones or other indicators tonote different levels of concern or criticality. The dataflow diagram ofFIG. 23A depicts one example of the steps performed by the drug deliverymanaging software and/or logic for one such protocol, namely, one whereelectronic controller 14 (e.g., FIG. 2A) receives an electronic feedbackvalue from an O₂ tank pressure sensor (519) indirectly measuring theamount of oxygen remaining in an on-board oxygen tank (the valueindicated by “O₂ remaining”). As is shown, the O₂ remaining value iscompared with an established data set of safe system parameters storedin a memory device as described above, said data set containing a“setpoint” reflecting known safe and undesirable oxygen tank pressureconditions (520). If the oxygen pressure is greater than the setpoint,no alarm sounds and no adjustment to drug delivery is effected (521). Ifthe O₂% value is less than the setpoint, alarm “1” sounds (522). Ifalarm “1” is silenced manually within 15 seconds, no further action istaken by the system (523). If alarm “1” is not silenced within 15seconds, the amount of drug being delivered (in this example gaseousN₂O) is reduced to the lesser of the concentration of 45% or the currentconcentration minus 10% (524). The software or logic procedure wouldoperate in a similar fashion for intravenous and nebulized forms ofdrugs and the instructions provided (e.g., as in 524), would bespecified for safe dosages of such drugs.

In another example of FIG. 21A involving a system state monitor whichindicates whether power is being supplied to apparatus 10, a logicoperation determines whether power has been interrupted. If the systemstate monitor for power signals that power has been interrupted, alarm“2” sounds and the delivery of drug is reduced to 0%.

Similar protocols are described in FIG. 21A for system state monitorsindicating O₂ interruption fail safe, total gas flow, drug tankpressure, fraction of inspired oxygen (FIO₂), and operation of thevacuum pump for scavenging system 48 (FIG. 6). These protocols areeffected with software (and/or logic) operating in similar fashion tothat described in the dataflow diagram of FIG. 23A. That is, theprotocol shown in FIG. 23A is one example employing one system statemonitor stored parameters, but the operation would be similar to effectthe remaining protocols of FIG. 21A.

In the above examples, involving response to patient physiologicalstate, there is a time lapse between the alarm's sounding and anydecrease in drug delivery to the patient. In alternate protocolscontemplated by the invention, electronic controller 14 will immediatelycease or curtail drug administration upon the sounding of an alarm. Forless critical (“yellow”) alarms, drug delivery may be decreased to 80%levels upon the sounding of the alarm; for more critical (“red”) alarms,drug delivery would cease upon the sounding of the alarm. In eithercase, the physician will then be given time, for example, thirtyseconds, to instruct controller 14 to restart the drug delivery (e.g.,the physician will need to override the curtailing of drug delivery). Ifthe physician does override controller 14, drugs are reinitiated, forexample, by a bolus amount. This method prevents against a patient'sdeteriorating while a physician waits to respond to an alarm at currentdrug levels, and also avoids underdosing by permitting the physiciansufficient time to reinitiate drug delivery.

Referring again to FIGS. 2 and 18, a printer 238 (FIG. 2, 37) providesan on-site hard copy of monitored patient health parameters (e.g., thefeedback values from the one or more patient health monitors), as wellas alarm states with time stamps indicating which type of alarmssounded, why and when. Diagnostic LEDs 240 affixed to the exterior ofapparatus 10 (e.g., FIG. 1) and electronically coupled to controller 14permit the physician typically involved in the procedure to ascertainsystem states at a glance; LEDs coupled to microprocessor controller 14also permit service technicians to assess fault states.

A preferred embodiment of the invention includes a variety of peripheralelectronic devices, one group internal to or integrated within housing15 of apparatus 10 (e.g., FIG. 1) and a second group on-board electroniccontroller 14. These electronic devices ensure proper operation ofvarious aspects of system 10, including providing hardware statusfeedback through sensors to ensure that the apparatus is operatingwithin its desired parameters. FIGS. 19A and 19B describe variousperipheral devices in accordance with the invention, such devices may beof a known, off-the-shelf types currently available. Specifically,internal solenoid-type activated door locks 190 restrict access to theinterior of apparatus 10. Door locks 190 are located within housing 15(FIG. 1) and are electronically coupled to and controlled by controller14 by means of software that includes protocols for password protection.Access to the interior of apparatus 10 is thus restricted to authorizedpersonnel with passwords. This is intended to, among other things,minimize chances of “recreational” abuse of the pharmaceuticals (e.g.,N₂O) contained therein. Internal door status sensors 191 located withinhousing 15 and electronically coupled to controller 14 generate signalsindicating if an access door to the interior of apparatus 10 is open orclosed. Real-time clock 192 on-board controller 14 enables saidcontroller 14 to provide time stamps for overall system and patientactivities and thereby enables creation of an accurate log of theoperation of care system 10. On-board ambient temperature sensor 193monitors the exterior temperature signaling same to controller 14 whichthrough software comparison type protocols confirms that apparatus 10 isbeing operated under desired conditions with respect to surroundingtemperature. Internal battery temperature sensor 194 located withinhousing 15 and electronically coupled to controller 14 generates signalsto same indicating whether the back-up battery power system isfunctioning correctly and not overcharging. Tilt sensor 195 locatedon-board controller 14 signals same if the apparatus 10 is beingoperated at an angle beyond its designed conditions.

In a preferred embodiment, the software control processes of electroniccontroller 14 are stored in a standard flash memory 196 and SRAM typebattery-backed memory 197 stores system, patient and other statusinformation in the event of an AC power loss. On-board fault detectionprocessor (FDP) 198 signals failures to controller 14 and is a secondarymicroprocessor based computing system which relieves controller 14 ofits control duties if a fault is detected in operation. On-board watchdog timer 199 indicates to controller 14 that the apparatus 10 isfunctioning and resets controller 14 if system 10 fails to respond.

A preferred embodiment of the invention also includes a standard serialport interface, such as an RS-232C serial port, for data transfer to andfrom electronic controller 14. The port enables, for example,downloading software upgrades to and transfer of system and patient logdata from controller 14. An interface such as a PC Type III slot is alsoprovided to enable the addition of computer support devices to system10, such as modems or a LAN, to be used, for example, to transferbilling information to a remote site; or to permit diagnosis of problemsremotely thereby minimizing the time required for trouble-shooting andaccounting.

It should be understood that the care system of the invention may bemodular in nature with its functions divided into separable, portable,plug-in type units. For example, electronic controller 14, displaydevices (FIG. 2, 35) and one or more patient health monitors would becontained in one module, the pneumatic systems (flow controllers,pressure regulators, manifold) in a second module, and the base (FIG.3B, 17), oxygen and drug tanks (FIG. 2, 54), scavenger system and vacuumpump (FIG. 3B, 32) in a third module. Additionally, the patient healthmonitors or drug delivery aspects of the system may each be their ownplug-in type modules. The system, for example, may provide for apluggable ventilator type module. This modularity enables the system notonly to be more easily portable, but also enables use of certainfeatures of the system (such as certain patient health monitors), whilenot requiring use of others.

FIG. 20 depicts a preferred embodiment of a patient information andbilling system capable of being interfaced with care system 10 (FIG. 1)to allow billing or other gathering of patient information to take placelocally at the place of use or remotely at a billing office.Specifically, information/billing storage system 280, which may be of aknown type microprocessor-based computing system controlled by software,collects and stores patient data 281 such as the patient's name, addressand other account information, as well as metered system operation data282 generated during operation of apparatus 10 and stored in controller14 such as start time, time of use, frequency of use, duration ofpatient monitoring, amount of gases expended, and other such parameters.User access device 283 which may be of a standard keyboard type permitsthe physician to interact with information/billing storage system 280 toinput additional data such as pre-determined treatment or billingparameters or to read the status of same (e.g., to read the status ofmetered system operation parameters 282). Preferably, a password isprovided to permit access to information/billing system 280.

At the termination of a medical or surgical procedure or at some otherdesired period, information/billing storage system 280 processes thereceived data and transmits same to revenue/billing processing center286 at a remote location. Revenue/billing processing center 286 may beof a known, mainframe-type computing system such as that manufactured byInternational Business Machines (IBM) or a known client-server typecomputer network system. At the remote location a patient invoice isgenerated by printer 287 as may be other revenue records used forpayment to vendors, etc.

The invention also contemplates that an automated record of the systemoperation details will be printed at the user site on printer 285 whichis preferably located on-board apparatus 10 (FIG. 1). Such systemoperation details may include, for example, all alarm and actual systemoperation states, drug flow rates and/or monitored actual patientphysiological conditions as supplied by electronic controller 14. Amodem or LAN may be used to send and receive billing and otherinformation remotely and to communicate with remote client/server orother networks 288 as described above.

1. A device to provide sedation to a patient, said device comprising: a drug delivery mechanism for delivering a drug dosage rate of sedative to said patient during a procedure; a patient health monitor adapted so as to be coupled to a patient during said procedure, said monitor generating a signal reflecting measurements of at least one monitored physiological condition of the patient; and a processor operably connected to said patient health monitor and said drug delivery device; said processor having accessible parameters that indicate values for said measurements of said monitored physiological condition, said values correlating to a range of patient conditions associated with said procedure; and wherein said processor operates according to software to receive said signal during said procedure, analyze said measurements reflected in said signal using said parameters to identify onset or possible onset of a patient condition outside of a normal range, and generate a signal indicating possible modifications of said drug dosage rate to remedy said onset or possible onset of said patient condition, wherein said processor signal indicates an action dependent upon an extent by which said current measurements are outside said normal range.
 2. The device as recited in claim 1, further comprising a fail safe system adapted to ensure proper operation of said device.
 3. The device as recited in claim 1, wherein said processor employs an algorithm conforming to target-controlled infusion rates for controlling said drug delivery mechanism.
 4. The device as recited in claim 1, wherein said patient health monitor is adapted to generate measurements reflecting effective spontaneous ventilation of the patient.
 5. The device as recited in claim 1, wherein said patient health monitor comprises a brain activity monitor.
 6. The device as recited in claim 1, wherein said patient health monitor is adapted to monitor a patient's end tidal carbon dioxide levels in an exhaled air stream of the patient.
 7. The device as recited in claim 1, wherein said patient health monitor device comprises a capnometer.
 8. The device as recited in claim 1, wherein said processor receives said signal during said procedure and identifies any onsets or possible onsets of patient condition episodes outside of a desired range through said comparison, and wherein said processor modifies said supply rate if necessary to remedy said episode.
 9. The device as recited in claim 1, wherein said drug delivery mechanism includes means for delivering said sedative intravenously.
 10. The device as recited in claim 1, wherein said parameters indicate values for said measurements of said monitored physiological condition that reflect the onset of potentially undesirable patient conditions during said procedure.
 11. The device as recited in claim 10, wherein said parameters indicate values for said measurements of said monitored physiological condition that reflect the onset of potentially unsafe patient conditions during said procedure.
 12. The device as recited in claim 1, further comprising a second health monitor adapted to be coupled to a patient and generate a second signal reflecting second measurements of a second physiological condition of the patient; and wherein said processor further contains second parameters indicating second values for said second measurements of said second physiological condition where said processor operates to receive said second signal, compare said second measurements reflected in said received second signal with said second parameters, and modify said dosage rate in response to said signal and said second signal as necessary to maintain safe and effective sedation during said procedure.
 13. The device as recited in claim 1, wherein said drug delivery mechanism is electronically controllable to provide drug delivery according to infusion types selected from the group consisting of continuous infusion, target controlled intravenous infusion, bolus infusion, and combinations thereof.
 14. The device as recited in claim 1, further comprising a recording means that creates records regarding patient conditions during said procedure.
 15. The device as recited in claim 14, wherein said records created by said recording means further include drug usage data during said procedure.
 16. The device as recited in claim 1, further comprising a manual input mechanism for permitting personnel performing the procedure to manually alter delivery of the sedative.
 17. The device as recited in claim 16, wherein said input mechanism permits said personnel performing the procedure to increase a current dosage rate of drug delivery.
 18. The device as recited in claim 17, wherein said values define a preset normal range of measurements of said monitored physiological condition for a patient undergoing said procedure, and wherein said processor controls said drug delivery mechanism by changing a drug dosage rate as necessary to maintain safe and effective sedation during said procedure.
 19. The device as recited in claim 18, wherein said preset normal range is identified by at least one threshold for said measurements.
 20. The device as recited in claim 19, wherein said values define at least two thresholds concerning said physiological condition, wherein said thresholds designate different levels of concern for said patient when said measurements move outside of said preset normal range.
 21. The device as recited in claim 1, wherein said values define a preset normal range of measurements of said monitored physiological condition for a patient undergoing said procedure, said preset normal range of measurements corresponding to potential physiological conditions of a patient that is receiving propofol by continuous intravenous infusion.
 22. The device as recited in claim 1, further including at least one alarm that is raised when said signal is determined to fall outside of said values correlating to safe and effective patient sedation during said procedure.
 23. The device as recited in claim 22, wherein said processor curtails drug delivery upon the raising of said alarm if an unsafe patient condition is identified.
 24. The device as recited in claim 22, wherein said processor increases the delivery of oxygen to the patient upon the raising of said alarm.
 25. The device as recited in claim 22, wherein said alarm is adapted to produce alarms of multiple urgency levels as defined by said parameters.
 26. The device as recited in claim 22, wherein said system also includes a display with an alarm box portion which displays a representation of the patient physiological condition associated with the raised alarm.
 27. The device as recited in claim 26, wherein said monitored physiological condition is selected from the group consisting of a brain activity, heart rate, blood saturation, expired carbon dioxide, ventilation, and patient consciousness level.
 28. The device as recited in claim 1, further comprising at least one system state monitor which generates a signal reflecting the state of at least one operating condition of the device and which is coupled to the processor; and wherein said processor has access to parameters indicating one or more operating conditions of the device.
 29. The device as recited in claim 28, wherein said system state monitor is an oxygen source pressure sensor that measures the flow of oxygen to the patient.
 30. The device as recited in claim 28, wherein said system state monitor indicates whether there has been a power failure in the device.
 31. The device as recited in claim 28, wherein said processor activates an attention-commanding device in response to said signal reflecting the state of at least one operating condition of the device.
 32. The device as recited in claim 28, wherein said system state monitor is a drug source flow sensor that measures flow of drug to the patient.
 33. The device as recited in claim 1, wherein said signal causes a communication device to raise an alarm regarding the condition of said patient, said alarm suggesting said possible modifications.
 34. The device as recited in claim 33, wherein said possible modifications include a default action to be taken by said drug delivery mechanism, wherein said default action is performed by said drug delivery mechanism in the absence of contrary instructions from medical personnel within a time period after said alarm is raised.
 35. The device as recited in claim 34, wherein said default action comprises said drug delivery mechanism device decreasing said drug dosage rate.
 36. A device for providing sedation to a patient during a medical and/or surgical procedure, said device comprising: an electronic drug delivery device adapted to be coupled to said patient and deliver to said patient one or more drugs at a drug delivery rate to provide sedation; a monitor adapted to be coupled to the patient and provide feedback indicative of at least one monitored physiological condition of the patient; a processor connected to said monitor, said processor receiving said feedback from said monitor and comparing said feedback to parameters that define whether a given patient is experiencing or in danger of experiencing an undesirable patient condition while receiving said drug at said drug delivery rate, and said processor thereby generating a signal reflecting the monitored physiological condition of the patient and indicating modifications of said drug delivery to avoid said undesirable patient condition during said medical procedure.
 37. The device as recited in claim 36, wherein said processor is further adapted to communicate an alarm to said medical personnel in response to said signal, said alarm indicating that a possible modification of said drug delivery may need to occur to avoid said undesirable patient condition.
 38. The device as recited in claim 37, wherein said electronic drug delivery device allows manual altering of delivery of drug by medical personnel in response to said feedbacks.
 39. The device as recited in claim 37, wherein said processor is further adapted to communicate an alarm to said medical personnel in response to said signal, said alarm indicating that a possible modification of said drug delivery may need to occur to remedy an undesirable patient condition.
 40. The device as recited in claim 37, wherein said alarm alerts a medical personnel of possible therapeutic options; said therapeutic options being identified by said comparison.
 41. The device as recited in claim 36, wherein said monitor is selected from the group consisting of an electrocardiograph, a pulse oximeter, a brain activity monitor, a capnometer, a blood pressure monitor and a patient consciousness monitor.
 42. The device as recited in claim 36, wherein said parameters define a preset normal range of said feedback for a patient undergoing said procedure, and wherein said modifications of drug delivery comprises decreasing a current drug delivery rate or raising an alarm if said monitored physiological condition of the patient moves outside of said preset normal range.
 43. The device as recited in claim 42, wherein said preset normal range is identified by at least one threshold for said feedback.
 44. The device as recited in claim 43, wherein said parameters define at least two thresholds concerning said feedback, and wherein said thresholds designate different levels of concern for said patient when said feedback is outside of said preset normal range.
 45. The device as recited in claim 36, wherein delivering of the drugs is accomplished by target-controlled infusion.
 46. The device as recited in claim 36, wherein said monitor is a brain activity monitor and said controlling of said drug delivery device comprises causing said drug delivery device to modify a supply rate of drug automatedly in response to said signal.
 47. The device as recited in claim 36, wherein said monitor is a pulse oximeter and said controlling of said drug delivery device comprises causing said drug delivery device to modify a supply rate of drug in response to changes in a monitored blood oxygen level of the patient.
 48. The device as recited in claim 36, wherein said monitored physiological condition is effective spontaneous ventilation of the patient.
 49. The device as recited in claim 36, wherein said monitor is a blood pressure monitor.
 50. The device as recited in claim 36, further comprising means for creating a record detailing control of said drug delivery during said procedure.
 51. The device as recited in claim 50, wherein said record further details information regarding said monitored physiological condition.
 52. The device as recited in claim 50, wherein said record further details alarms generated in response to said signal.
 53. The device as recited in claim 36, wherein said drug delivery device is adapted to perform a delivery mechanism selected from the group consisting of continuous infusion, target controlled infusion, bolus infusion, and combinations thereof.
 54. The device as recited in claim 36, wherein said processor further receives a second signal reflecting a state of at least one operating condition of said drug delivery device or said monitor, said signal being received by said processor, and said processor thereby initiating alarms if said operating condition is unsatisfactory.
 55. The device as recited in claim 54, wherein said operating conditions are of types selected from the group consisting of oxygen flow status, power failures, and drug flow status.
 56. The device as recited in claim 36, wherein said monitored physiological condition is the patient's level of consciousness.
 57. A device for sedating a patient undergoing one or more medical and/or surgical procedures, said device comprising: a drug delivery device adapted to be connected to a patient and capable of controllable drug delivery to the patient during a procedure; an electronic controller coupled to said drug delivery device, said controller adapted to control the delivery of drugs by said drug delivery device; a patient health monitor device to a patient, said health monitor device generating a signal reflecting at least one monitored physiological condition of the patient, said signal being sent from said health monitor device to said electronic controller to communicate a current measurement reflecting said monitored physiological condition of the patient; and wherein said electronic controller accesses parameters for said monitored physiological condition, said parameters including values for said measurements of said monitored physiological condition where said values correlate to safe and effective sedation during said procedure, said electronic controller compares said measurement reflected in said received signal with said parameters, and said electronic controller modifies a supply rate of the drugs according to software to maintain safe and effective sedation of the patient during said procedure, said electronic controller modifying said supply rate to an extent being dependent upon a second extent by which said measurement is outside one or more ranges defined by said parameters.
 58. The device as recited in claim 57, wherein said patient health monitor device is selected from the group consisting of an electrocardiograph, a pulse oximeter, a brain activity monitor, a capnometer, a blood pressure monitor and a patient consciousness monitor.
 59. The device as recited in claim 57, wherein said one of said ranges is defined by values that establish a preset normal range of said measurements for a patient undergoing said procedure, and wherein said modifying of said drug delivery rate comprises said electronic controller decreasing a current drug delivery rate or raising an alarm if said monitored physiological condition of the patient moves outside of said preset normal range.
 60. The device as recited in claim 59, wherein said preset normal range is identified by at least one threshold for said measurements.
 61. The device as recited in claim 60, wherein said values establish at least two thresholds concerning said physiological condition, and wherein said thresholds designate different levels of concern for said patient when measurements are outside of said preset normal range.
 62. The device as recited in claim 57, wherein said values define measurements of said monitored physiological condition that evidence the onset of potentially undesirable patient conditions during said procedure.
 63. The device as recited in claim 57, wherein said electronic controller modifies said supply rate according to a target-controlled infusion algorithm.
 64. The device as recited in claim 57, wherein said patient health monitor device is a brain activity monitor and said modifying of said supply rate of drug is in response to a concentration of drug in the patient.
 65. The device as recited in claim 57, wherein said patient health monitor device is a pulse oximeter and the modifying of said supply rate of the drug is in response to changes in a monitored blood oxygen level of the patient.
 66. The device as recited in claim 57, wherein said monitored physiological condition is effective spontaneous ventilation of the patient.
 67. The device as recited in claim 57, wherein said monitor device is a blood pressure monitor.
 68. The device as recited in claim 57, further comprising means for creating a record detailing delivering of said drug during said one or more procedures.
 69. The device as recited in claim 68, wherein said record further details information regarding said monitored physiological condition.
 70. The device as recited in claim 57, wherein said drug delivery device is further adapted to permit manual altering the delivery of drug.
 71. The device as recited in claim 70, wherein said manual altering comprises increasing a current rate of drug delivery to the patient.
 72. The device as recited in claim 57, wherein said electronic controller receives a signal reflecting a state of at least one operating condition of said drug delivery device or said patient health monitor device, and said controller is adapted to initiate alarms if said operating condition is unsatisfactory.
 73. The device as recited in claim 72, wherein said operating conditions are of types selected from the group consisting of oxygen flow status, power failures, and drug flow status.
 74. The device as recited in claim 57, wherein said monitored physiological condition is the patient's level of responsiveness. 